General Biology 1 2nd Trimester PDF

.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION CHAPTER 1: THE SCIENCE OF LIFE II. LIFE AND IT’S BEGINNINGS I. BRANCHES OF BIOLOGY Biology lite...

.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION CHAPTER 1: THE SCIENCE OF LIFE II. LIFE AND IT’S BEGINNINGS I. BRANCHES OF BIOLOGY Biology literally means the study of life. ORIGIN OF LIFE FROM DIFFERENT PERSPECTIVES It deals with the structures, functions, and 1. Redi’s Experiment relationships of living things to their environment ○ Life comes from life ○ Disproved the idea of spontaneous generation 3 DIVISIONS OF BIOLOGICAL SCIENCE using meat and flies. Showed that maggots only Microbiology appeared on meat when flies were allowed to land ○ Study of microorganisms on it. Botany 2. Needham’s Experiment ○ Study of plants ○ Life comes from nonlife Zoology ○ Attempted to support spontaneous generation by ○ Study of animals boiling nutrient broth and observing microbial growth. TRADITIONAL BRANCHES OF BIOLOGY 3. Spallanzani’s Experiment Anatomy ○ Life cannot come from nonlife ○ It is the study of structures and parts of organisms. ○ Repeated Needham's experiment but sealed the Evolution flasks after boiling to prevent contamination. ○ It is the study of origin and differentiation of Showed that no growth occurred unless the flask various organisms. was opened, refuting spontaneous generation. Genetics 4. Pasteur’s Experiment ○ It is the study of heredity and variation. ○ Particles in the air created life (contaminated) Cytology ○ Designed a flask with a curved neck that allowed ○ It is the study of structures and functions of cells. air in but prevented dust and microbes from Taxonomy entering. Showed that microbial growth did not ○ It is the study of naming and classifying occur in the sterile broth, supporting the idea of organisms. biogenesis. Physiology 5. Divine Creation ○ It is the study of functions of living organisms and ○ The belief that life was created by a divine force or their parts. deity. It is often associated with religious Biochemistry explanations for the origin of life. ○ It is the study of biochemical compositions and 6. Spontaneous Origin processes of living things. ○ Life comes from nonliving things if it contained Ecology pneuma (vital heat) ○ It is the study of relationships of organisms with ○ Belief from Aristotle that living organisms can each other and their environment. arise spontaneously from non-living matter Embryology 7. Panspermia ○ It is the study of formation and development of ○ The hypothesis that life on Earth, or at least the organisms. key components for life, may have originated from extraterrestrial sources, such as meteoroids, MODERN BRANCHES OF BIOLOGY comets, or cosmic dust. Bioinformatics ○ Suggests that life's building blocks were delivered Genomics to Earth from space. Molecular Biology Pharmacogenomics III. WHAT IS LIFE Proteomics All organisms share common characteristics that guide Synthetic Biology in defining what one means by life. Systems Biology.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION SCIENTIFIC STUDY OF LIFE organism living in the same place and time Example: Multiple acacia trees Community All populations that occupy the same region Example: All populations in a savanna Ecosystem The living and nonliving components of an area Example: The savanna Biosphere The global ecosystem; the parts of the planet and its atmosphere where life is possible Cells are the basic units of life. Every organism, or ○ Emergent properties arise at each level of living individual, consists of one or more cells. biological organization. Cells use DNA to produce proteins. - Unique characteristics that arise at a higher level of organization in a system among 5 CHARACTERISTICS OF LIFE smaller parts that do not exhibit such 1. Organization properties alone and are not present at lower ○ Life is organized. levels of organization. Biological - Example: Brain Cells → Interacting Brain Definition Cells → Brain → Emergent Property: Memory Organization - Memory has properties that its components Atom The smallest chemical unit of a type of alone lack. pure substance (element) Example: Carbon atom 2. Energy Use Molecule A group of joined atoms ○ Life requires energy. Example: DNA ○ Plants use photosynthesis to harness energy from sunlight, trapping it with their leaves Organelle A membrane-bound structure that has - Heat is lost every time energy is transferred. a specific function within a cell 10% is only absorbed every time something is Example: Chloroplast eaten. Cell The fundamental unit of life ○ Cellular respiration is the process by which Example: Leaf cell energy is released by the breakdown of food. ○ Metabolism is the sum of all chemical processes Tissue A collection of specialized cells that and energy changes happening inside the body of function in a coordinated fashion an organism. Example: Epidermis of leaf - These chemical reactions that power organisms' life processes and provide them Organ A structure consisting of tissues organized to interact and carry out with raw materials are performed in specific functions sequence and regulated. Example: Leaf - Include nutrient uptake, nutrient processing, and waste elimination. Organ Organs connected physically or - Anabolism is the building up of energy. System chemically that function together - Catabolism is the breakdown of energy. Example: Aboveground part of a plant Organism A single living individual Example: One acacia tree Population A group of the same species of.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION 3. Maintenance of Internal Constancy First To View Cells ○ Life maintains internal constancy. ○ Robert Hooke ○ Homeostasis is the process by which a cell or - In 1665, he used a microscope to examine a organism maintains equilibrium thin slice of cork (dead plant cell walls) - A thermostat is an analogy for how life - what he saw looked like small boxes maintains internal constancy. - Hooke is responsible for naming cells - Humans have an internal thermostat that - Hooke called them “cells” because they helps maintain temperature homeostasis.. looked like the small rooms that monks lived - Homeostasis is not just about temperature in called Cells though. For example, organisms also fluctuate ○ Anton van Leeuwenhoek around their optimal nutrient, salt, and water - In 1673, Leeuwenhoek (a Dutch microscope balances. maker), was first to view organism (living things) 4. Reproduction, Growth, and Development - Leeuwenhoek used a simple, handheld ○ Life reproduces itself, grows,and develops. microscope to view pond water & scrapings ○ Reproduction is either asexual or sexual. from his teeth ○ Offspring of asexually reproducing organisms are Beginning of Cell Theory identical to their single parent, such as the ○ The cell theory was only formulated after nearly plantlets developing along the strawberry runners. 200 years since the introduction of microscopy - Asexual reproduction is a successful ○ Lorenz Oken (1779-1851) strategy in unchanging environments. - postulated in 1805 that all organisms ○ Offspring of sexually reproducing organisms originate from and consist of cells. This receive genetic material from two parents, such became the initial statement of the modern as the two swan offspring created by the male and cell theory female adult swans. ○ Robert Brown (1773-1858) - Sexual reproduction is successful in - He discovered the nucleus in 1833 as a changing environments, since offspring are constant part of the plant cells. Then the unlike either parent nuclei were also found and observed in some ○ Most plants and animals reproduce sexually. animal Some have the option to reproduce asexually. ○ Felix Dujardin (1801-1860) - French biologist 5. Evolution - He first recognized the living substance within ○ Life evolves. the cell in 1835 which he termed as ○ How is it that so many organisms seem perfectly “sarcode”. suited to their environment? ○ Jan Evangelista Purkinje (1787-1869) ○ This pygmy seahorse camouflages with the coral - He changed the term sarcode to protoplasm, habitat. Seahorses that blend in best, have lower referring to the colloidal substance in the cell. predation rates. Now called cytoplasm. ○ Bacteria evolve quickly. Antibiotic-resistant ○ Matthias Schleiden bacteria are most successful. - In 1838, the German botanist concluded that all plants were made of cells CHAPTER 2: THE CELL - Schleiden is a cofounder of the cell theory ○ Theodore Schwann I. CELL - In 1839, the German zoologist concluded that all animals were made of cells HISTORY OF CELLS & CELL THEORY - Schwann also co founded the cell theory Early 1600’s ○ Rudolph Virchow ○ Zacharias Jansen (1588 - 1631) - In 1855, the German medical doctor observed, - a Dutch lens maker under the microscope, cells dividing - invented the first microscope prototype - He reasoned that all cells come from other pre-existing cells by cell division.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION ○ Cell Theory in a nutshell (Matthias Schleiden + ORGANIZATION LEVELS OF LIFE Theodore Schwann + Rudolph Virchow) Atoms to Organisms - All living things are composed of one or Nonliving Levels: more cells. ○ Atoms - Cells are the basic unit of structure and ○ Molecules function in an organism (basic unit of life). ○ Organelles - Cells come from the reproduction of existing Living Levels: cells (cell division). ○ Cells - life starts here DISCOVERIES SINCE THE CELL THEORY ○ Tissues Endosymbiotic Theory - similar cells working together ○ In 1970, American biologist, Lynn Margulis, ○ Organs provided evidence that some organelles within - different tissues working together cells were at one time free living cells ○ Organ Systems themselves - different organs working together ○ Supporting evidence included organelles with ○ Organism their own DNA ○ Chloroplast and Mitochondria SIMPLE OR COMPLEX CELLS Prokaryotes CELL SIZE AND TYPES ○ The first cells Cells, the basic units of organisms, can only be ○ Cells that lack a nucleus or membrane-bound observed under microscope organelles Three Basic types of cells include: ○ Includes bacteria ○ Animal Cell ○ Simplest type of cell ○ Plant Cell ○ Single, circular chromosome ○ Bacterial Cell ○ Nucleoid region (center) contains the DNA Number of Cells ○ Surrounded by cell membrane & cell wall ○ Typical cells range from 5 – 50 micrometers (peptidoglycan) (microns) in diameter ○ Contain ribosomes (no membrane) in their ○ Although ALL living things are made of cells, cytoplasm to make proteins organisms may be: Eukaryotes - Unicellular – composed of one cell ○ Cells that have a nucleus and membrane-bound - Multicellular – composed of many cells that organelles may organize into tissues, etc. ○ Includes protists, fungi, plants, and animals Cells in multicellular organisms often ○ More complex type of cells specialize (take on different shapes & ○ Two Main Types of Eukaryotic Cells: functions) - Plant Cell (Cuboidal) Plant Cells > Animal Cells > Bacterial Cells Contain 4 basic cell structures under a compound microscope: CELL SPECIALIZATION ★ Nucleus Cells in a multicellular organism become ★ Cell wall specialized by turning different genes on and off ★ Cell Membrane This is known as differentiation ★ Cytoplasm Specialized Animal Cells: - Animal Cell (Round) ○ Muscle Cells Contain 3 basic cell structures under a ○ Red blood Cells compound microscope: ○ Cheek Cells ★ Nucleus Specialized Plant Cells: ★ Cell Membrane ○ Guard Cells ★ Cytoplasm ○ Xylem Cells ○ Pollen.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION ORGANELLES - Pushes out against the cell wall to maintain Very small (Microscopic) cell shape Perform various functions for a cell Found in the cytoplasm Cell Wall (PLT) May or may not be membrane-bound ○ Non Living layer ○ Found in plants, fungi, & bacteria ○ Made of cellulose in plants ○ Made of peptidoglycan in bacteria ○ Made of chitin in fungi ○ Supports and protects the cell ○ Found outside of the cell membrane Cytoplasm (ANM / PLT) ○ Jelly-like substance enclosed by cell membrane ○ Provides a medium for chemical reactions to take place ○ Contains organelles to carry out specific jobs ○ Found in all cells ○ Visible under a microscope Cell or Plasma Membrane (ANM / PLT) Nucleus (ANM / PLT) ○ Composed of double layer of phospholipids and ○ The control organelle proteins ○ Controls the normal activities of the cell ○ Surrounds the outside of all cells ○ Contains the DNA in chromosomes ○ Controls what enters or leaves the cell ○ Cell reproduction ○ Living layer ○ Bounded by a nuclear envelope (membrane) with ○ Phospholipids pores - Heads contain glycerol & phosphate and are ○ Usually the largest organelle hydrophilic (attract water) ○ Each cell has fixed number of chromosomes - Tails are made of fatty acids and are that carry genes hydrophobic (repel water) ○ Genes control cell characteristics - Make up a bilayer where tails point inward ○ Inside the nucleus: toward each other - The genetic material (DNA) is found - Can move laterally to allow small molecules - DNA is spread out and appears as (O2 , CO2 , & H2O to enter) chromatin in non-dividing cells ○ The Cell Membrane is Fluid - DNA is condensed & wrapped around - Molecules in cell membranes are constantly proteins forming as chromosomes in moving and changing dividing cells ○ Cell Membrane Proteins - What does DNA do? - Proteins help move large molecules or aid in DNA is the hereditary material of the cell cell recognition Genes that make up the DNA molecule - Peripheral proteins are attached on the code for different proteins surface (inner or outer) - Integral proteins are embedded completely Nuclear Envelope (ANM / PLT) through the membrane ○ Double membrane surrounding nucleus ○ Glycoproteins ○ Also called nuclear membrane - Glycoproteins have carbohydrate tails to act ○ Contains nuclear pores for materials to enter & as markers for cell recognition leave nucleus ○ Cell Membrane in Plants ○ Connected to the rough ER - Lies immediately against the cell wall in plant cells Nucleolus (ANM / PLT).GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION ○ Inside nucleus - They are then threaded into the interior of ○ Cell may have 1 to 3 nucleoli the Rough ER to be modified and ○ Disappears when cell divides transported ○ Makes and assembles ribosomes that make ○ Smooth ER proteins - Smooth ER lacks ribosomes on its surface - Is attached to the ends of rough ER Cytoskeleton (ANM / PLT) - Makes cell products that are used inside the ○ Helps cell maintain cell shape cell ○ Also help move organelles around - Makes membrane lipids (steroids) ○ Made of proteins - Regulates calcium (muscle cells) ○ Microfilaments are threadlike & made of Actin - Destroys toxic substances (Liver) ○ Microtubules are tubelike & made of Tubulin Endomembrane System (ANM / PLT) Centrioles (ANM) ○ Includes nuclear membrane connected to ER ○ Found only in animal cells connected to cell membrane (transport) ○ Paired structures near nucleus ○ Made of bundle of microtubules Ribosomes (ANM / PLT) ○ Appear during cell division forming mitotic ○ Made of proteins and rRNA spindle ○ “Protein factories” for cell ○ Help to pull chromosome pairs apart to ○ Join amino acids to make proteins opposite ends of the cell ○ Process called protein synthesis ○ Attached to the rough ER or free in the cytoplasm Mitochondrion (ANM / PLT) ○ “Powerhouse” of the cell Golgi Apparatus (Bodies) (ANM / PLT) ○ Generates and stores cellular energy (ATP) ○ Stacks of flattened sacs ○ More active cells like muscle cells have more ○ Have a shipping side (trans face) and receiving mitochondria side (cis face) ○ Both plants & animal cells have mitochondria ○ Receive proteins made by ER ○ Site of cellular respiration (burning glucose) ○ Transport vesicles with modified proteins pinch ○ Surrounded by a double membrane off the ends ○ Has its own DNA ○ forms secretory vesicles ○ Folded inner membrane called cristae (increases ○ Modify, sort, & package molecules from ER for surface area for more chemical reactions) storage or transport out of cell ○ Interior called matrix ○ Materials are transported from Rough ER to ○ Mitochondria comes from cytoplasm in the egg Golgi to the cell membrane by vesicles. cell during fertilization ○ You inherit your mitochondria from your mother Lysosomes (ANM) ○ Sausage shape ○ Contain digestive enzymes ○ Break down food, bacteria, and worn out cell Endoplasmic Reticulum (ANM / PLT) parts for cells ○ Network of hollow membrane tubules ○ Programmed for cell death (autolysis or ○ Connects to nuclear envelope & cell membrane apoptosis) ○ Functions in protein synthesis and lipid ○ Lyse (break open) & release enzymes to break synthesis of cell products & transport down & recycle cell parts ○ Rough ER ○ Lysosome Digestion - Has ribosomes on its surface - Cells take in food by phagocytosis - Makes membrane proteins and proteins for - Lysosomes digest the food & get rid of export out of the cell wastes - Proteins are made by ribosomes on ER surface.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION Cilia & Flagella II. THE CELL CYCLE ○ Cilia are shorter and more numerous on cells ○ Flagella are longer and fewer (usually 1-3) on THE KEY ROLES OF CELL DIVISION cells The ability of organisms to produce more of their Vacuoles (PLT) own kind best distinguishes living things from ○ Fluid filled sacs for storage nonliving matter ○ Small or absent in animal cells The continuity of life is based in the reproduction of ○ Plant cells have a large central vacuole cells or cell division ○ No vacuoles in bacterial cells In unicellular organisms, division of one cell ○ In plants, they store Cell Sap reproduces the entire organism ○ Includes storage of sugars, proteins, minerals, Multicellular organisms depend on cell division for the: lipids, wastes, salts, water, and enzymes ○ Development from a fertilized cell ○ Growth Contractile Vacuole ○ Repair ○ Found in unicellular protists like paramecia Cell division is an integral part of the cell cycle. The ○ Regulate water intake by pumping out excess life of a cell from formation to its own division. (homeostasis) ○ Keeps the cell from lysing (bursting) FUNCTIONS OF CELL DIVISION Reproduction Chloroplasts (PLT) Growth and Development ○ Found only in producers (organisms containing Tissue Renewal chlorophyll) ○ Use energy from sunlight to make own food THE CELL CYCLE AND HOW CELLS DIVIDE (glucose) Phases of Cell Cycle ○ Energy from sun stored in the chemical bonds of ○ Cell cycle consists of: sugars - Interphase - normal cell activity ○ Surrounded by double membrane - Mitotic phase - cell division ○ Outer membrane smooth Cell Division ○ Inner membrane modified into sacs called ○ An integral part of the cell cycle Thylakoids ○ Results in genetically identical daughter cells ○ Thylakoids in stacks called Grana & ○ Cells duplicate their genetic material interconnected - Before they divide, ensuring that each ○ Stroma – gel like material surrounding daughter cell receives an exact copy of the thylakoids genetic material, DNA ○ Contains its own DNA - The exception is meiosis, a special type of ○ Contains enzymes & pigments for division that can produce sperm and egg photosynthesis cells ○ Never in animal or bacterial cells ○ Photosynthesis – food making process DNA Genetic Information - genome FACTORS AFFECTING CELL SIZE All the DNA in a cell constitutes the cell's genome Surface area (plasma membrane surface) is A genome consists of a single DNA molecule determined by multiplying length times width (L x W) (common in prokaryotic cells) or a number of DNA Volume of a cell is determined by length times width molecules (common in eukaryotic cells) times height (L x W x H) Packaged into chromosomes Therefore, Volume increases faster than the surface area When the surface area is no longer great enough to get rid of all the wastes and to get in enough food and water, then the cell must divide Therefore, the cells of an organism are close in size.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION DNA AND CHROMOSOMES Every 200 nucleotide pairs, the DNA wraps twice An average eukaryotic cell has about 1,000 times around a group of 8 histone proteins to form a more DNA than an average prokaryotic cell nucleosome. The DNA in a eukaryotic cell is organized into Higher order coiling and supercoiling also help several linear chromosomes, whose organization is condense and package the chromatin inside the much more complex than the single, circular DNA nucleus molecule in a prokaryotic cell The centromere is a constricted region of the chromosome containing a specific DNA sequence, CHROMOSOMES to which is bound 2 discs of protein called All eukaryotic cells store genetic information in kinetochores. chromosomes Kinetochores serve as points of attachment for ○ Most eukaryotes have between 10 and 50 microtubules that move the chromosomes during chromosomes in their body cells. cell division ○ Human cells have 46 chromosomes. Diploid - A cell possessing two copies of each ○ 23 nearly-identical pairs chromosome (human body cells). Non-homologous chromosomes ○ Homologous chromosomes are made up of sister ○ Look different chromatids joined at the centromere. ○ Control different traits Haploid - A cell possessing a single copy of each Sex chromosomes chromosome (human sex cells). ○ Are distinct from each other in their characteristics KARYOTYPE ○ Are represented as X and Y An ordered, visual representation of the ○ Determine the sex of the individual, XX being chromosomes in a cell female, XY being male Chromosomes are photographed when they are In a diploid cell, the chromosomes occur in pairs. highly condensed, then photos of the individual The 2 members of each pair are called homologous chromosomes are arranged in order of decreasing chromosomes or homologues. size A diploid cell has two sets of each of its In humans each somatic cell has 46 chromosomes, chromosomes made up of two sets, one set of chromosomes A human has 46 chromosomes (2n = 46) comes from each parent In a cell in which DNA synthesis has occurred all the chromosomes are duplicated and thus each CHROMOSOME DUPLICATION consists of two identical sister chromatids In preparation of cell division, DNA is replicated and the chromosomes condense HOMOLOGUES Each duplicated chromosome has two sister Homologous chromosomes chromatids, which separate during cell division ○ Look the same Because of duplication, each condensed ○ Control the same traits chromosome consists of 2 identical chromatids ○ May code for different forms of each trait joined by a centromere. ○ Independent origin - each one was inherited Each duplicated chromosome contains 2 identical from a different parent DNA molecules (unless a mutation occurred), one in each chromatid STRUCTURE OF CHROMOSOMES Chromosomes are composed of a complex of DNA PHASES OF THE CELL CYCLE and protein called chromatin that condenses during Interphase cell division ○ G1 Primary Growth DNA exists as a single, long, double-stranded fiber ○ S Genome Replicated extending the chromosome's entire length. ○ G2 Secondary Growth Each unduplicated chromosome contains one DNA M - Mitosis molecule, which may be several inches long C - Cytokinesis.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION INTERPHASE The chromosomes convene on the metaphase G1 - Cells undergo majority of growth plate, an imaginary plane that is equidistant S - Each chromosome replicates (Synthesizes) to between the spindle’s two poles. The chromosomes’ produce sister chromatids centromeres lie on the metaphase plate. ○ Attached at centromere For each chromosome, the kinetochores of the sister ○ Contains attachment site (kinetochore) chromatids are attached to kinetochore G2 - Chromosomes condense - Assemble machinery microtubules coming from opposite poles. for division such as centrioles The entire apparatus of microtubules is called the spindle because of its shape. A. MITOSIS The Mitotic Spindle Some haploid and diploid cells divide by mitosis ○ The spindle includes the centrosomes, the Each new cell receives one copy of every spindle microtubules, and the asters chromosome that was present in the original cell. ○ The apparatus of microtubules controls Produces 2 new cells that are both genetically chromosome movement during mitosis identical to the original cell. ○ The centrosome replicates, forming two Only happens in body cells centrosomes that migrate to opposite ends of the cell G2 OF INTERPHASE ○ Assembly of spindle microtubules begins in the A nuclear envelope bounds the nucleus. centrosome, the microtubule organizing center The nucleus contains one or more nucleoli (singular, ○ An aster (a radial array of short microtubules) nucleolus). extends from each centrosome Two centrosomes have formed by replication of a ○ Some spindle microtubules attach to the single centrosome. kinetochores of chromosomes and move the In animal cells, each centrosome features two chromosomes to the metaphase plate centrioles. ○ In anaphase, sister chromatids separate and Chromosomes, duplicated during S phase, cannot move along the kinetochore microtubules be seen individually because they have not yet toward opposite ends of the cell condensed. ANAPHASE PROPHASE Anaphase is the shortest stage of mitosis, lasting The chromatin fibers become more tightly coiled, only a few minutes. condensing into discrete chromosomes Anaphase begins when the two sister chromatids of observable with a light microscope. each pair suddenly part. Each chromatid thus The nucleoli disappear. becomes a full - fledged chromosome. Each duplicated chromosome appears as two The two liberated chromosomes begin moving identical sister chromatids joined together. toward opposite ends of the cell, as their kinetochore The mitotic spindle begins to form. It is composed of microtubules shorten. Because these microtubules are the centrosomes and the microtubules that extend attached at the centromere region, the chromosomes from them. The radial arrays of shorter microtubules move centromere first (at about 1 µm/min). that extend from the centrosomes are called asters The cell elongates as the nonkinetochore (“stars”). microtubules lengthen. The centrosomes move away from each other, By the end of anaphase, the two ends of the cell apparently propelled by the lengthening microtubules have equivalent — and complete —collections of between them. chromosomes. METAPHASE TELOPHASE Metaphase is the longest stage of mitosis, lasting Two daughter nuclei begin to form in the cell. about 20 minutes. Nuclear envelopes arise from the fragments of the The centrosomes are now at opposite ends of the parent cell’s nuclear envelope and other portions of cell. the endomembrane system. The chromosomes become less condensed..GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION Mitosis, the division of one nucleus into two Zygotene (Zipper Stage) genetically identical nuclei, is now complete. ○ Pairing of homologous chromosomes takes place called synapsis CYTOKINESIS ○ Bivalent - paired unit formed of homologous Cleavage of cell into two halves chromosomes consisting of a paternal and a ○ Animal cells maternal chromosome - Constriction belt of actin filaments Pachytene (Tetrad Stage) ○ Plant cells ○ Each bivalent shows four chromatids called - Cell plate tetrad ○ Fungi and protists ○ Genetic Crossing Over - exchange of genetic - Mitosis occurs within the nucleus material that takes place between the non sister chromatids of homologous chromosomes. B. MEIOSIS ○ Results to genetic recombination which is A division of the nucleus that reduces chromosome responsible for variations number by half (also called reduction division) ○ Chiasmata - visible expression of crossing over The daughter cells receive only half of the original Diplotene set of chromosomes of the parental cell ○ Terminalization occurs Helps to maintain the constant number of ○ The movement of chiasma towards the tips of chromosomes for a particular species. chromosomes as the homologous Occurs only in: chromosomes of bivalent start moving apart ○ germinal cells found in male gonad (testis) Diakinesis ○ female gonad (ovary) ○ Nucleolus and Nuclear membrane disappear ○ spore mother cells of plants ○ Chromosomes set free in the cytoplasm PHASES OF MEIOSIS METAPHASE I A diploid cell replicates its chromosomes Tetrads or homologous chromosomes move to Two stages meiosis center of cell ○ Meiosis 1 and Meiosis 2 ○ Only 1 replication ANAPHASE I Homologous chromosomes are pulled to opposite INTERPHASE I poles by the activity of spindle fibers. Duplication of DNA, centrioles and synthesis of This is called separation or disjunction of RNA and proteins take place chromosomes. MEIOSIS I TELOPHASE I KARYOKINESIS I The nuclear membrane reappears around the It is the division of nucleus that takes place in the chromosomes at each pole following stages. Daughter nuclei formed These are haploid (1n) PROPHASE I Involves 5 sub stages CYTOKINESIS I Leptotene (Bouquet Stage) A cleavage furrow develops in the middle of the cell ○ Chromatin condenses to form chromosomes in centripetal direction due to contraction of ○ Chromosomes appear as long, thin and microtubules. thread-like structures. ○ Centrioles form into asters and keep moving INTERKINESIS towards opposite poles The Interphase after the first meiotic division ○ Spindle apparatus begin to appear It may be present or absent between Meiosis - I and Meiosis - II. If present it may be short or in some cases Telophase - I directly enters Prophase - II..GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION MEIOSIS II MITOSIS VS. MEIOSIS Daughter cells undergo a second division; much Both are forms of nuclear division like mitosis Both involve replication No additional replication occurs Both involve disappearance of the nucleus, Undergoes karyokinesis II nucleolus, nuclear membrane Both involve formation of spindle fibers PROPHASE II Spindle fibers form again DIFFERENCES: MEIOSIS The nuclear envelope and nucleolus disintegrate Meiosis produces daughter cells that have 1/2 the and disappear number of chromosomes as the parent. Go from 2n to n. METAPHASE II Daughter cells produced by meiosis are not Chromosomes arrange in the equatorial region at genetically identical to one another. right angles to the asters In meiosis cell division takes place twice but Spindle fibers connect to the centromere replication occurs only once. Occurs in sex cells ANAPHASE II Daughter cells produced after cell division: 4 The centromeres of all the chromosomes undergo Number of chromosomes: haploid (n) longitudinal splitting. Chromatids of each chromosome separate and DIFFERENCES: MITOSIS they move towards opposite poles Daughter cells produced are genetically identical to one another. TELOPHASE II & CYTOKINESIS Occurs in body cells Four haploid daughter cells results from one original Daughter cells produced after cell division: 2 diploid cell Number of chromosomes: diploid (2n) A nuclear envelope is formed III. REGULATION OF CELL CYCLE G0 PHASE (QUIESCENT STAGE OR RESTING STAGE) The phase of the cell cycle during which a cell is FREQUENCY OF CELL DIVISION neither dividing nor preparing to divide. The cell Frequency of cell division varies by cell type cycle typically refers to the process by which the cell ○ Embryo can grow and repair itself - Cell cycle < 20 minutes Examples: mature cardiac muscle and nerve cells ○ Skin cells - Divide frequently throughout life SIGNIFICANCE OF MEIOSIS - 12-24 hours cycle It helps to restore diploidy ○ Liver cells Maintain the constant number of chromosomes for - Retain ability to divide but keep it in reserve a species - Divide once every year or two Results to variations which are the food for speciation ○ Mature nerve cells & muscle cells - Do not divide at all after maturity VALUE OF VARIATION - Permanently in G0 Variation - differences between members of a population. OVERVIEW OF CELL CYCLE CONTROL Meiosis results in random separation of Two irreversible points in cell cycle chromosomes in gametes. ○ Replication of genetic material Causes diverse populations that over time can be ○ Separation of sister chromatid stronger for survival. Checkpoints ○ Process is assessed and possibly halted.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION REGULATION OF THE CELL CYCLE CYCLE PHASES To enable the cell to maintain its appropriate size, cell G1 – First growth phase. growth and division must be coordinated all the ○ Metabolic activity proceeds at a normal rate. time Duration highly variable. Synthesis of enzymes Cells do not divide in situations where nutrients are related to DNA replication. short supply, since cell division is an G0 – Quiescent (rest) state. energy-demanding process ○ Usually for nonproliferative cells. Can occur for Most animal cells do not divide where there are no cells that are damaged. Alternative to apoptosis. instructions to divide. Can be temporary or permanent. Activated by both internal and external factors. ○ Nerve and muscle cells (multinucleated) S – DNA replication. CELL CYCLE CHECKPOINTS ○ All chromosomes replicated. The cell cycle is regulated by a molecular signaling ○ Chromosomes consist of 2 sister chromatids in system which switches the cell cycle control chromatin form. system on / off ○ Histones produced. The system consists of a molecular clock and ○ Chromosome checkpoints to ensure conditions are met before - 1 long string of DNA Sister chromatids moving on to the next steps - Loose - chromatin Malfunctions may lead to cancer. - Tight - chromatid Checkpoint in G1 phase ○ Prevents the cell from starting the S stage, until a EXTERNAL FACTORS growth-promoting signal has been received Come from outside the cell that are in the form of ○ The cell has achieved optimum size for growing messages from nearby cells or from remote parts of daughter cells the organism’s body. Checkpoint in G2 phase: Can also bind receptors that will later on trigger ○ The cell’s DNA has been copied before mitosis internal factors can occur Physical Signals: ○ If DNA has been damaged, the cell cycle stops ○ Cell-to-cell contact to undergo repair. If the situation is beyond ○ Contact Inhibition - a phenomenon when a cell repair, the cell undergoes self-destruction. touches another cell and stops dividing Checkpoint in Metaphase: ○ Anchorage Dependent - cells only grow if ○ Assures that the every kinetochore of every surface is available and stop dividing when chromatid has been attached to a spindle fiber detached from the culture dish before proceeding to anaphase Chemical Signals: ○ Ensures that daughter cells have received the ○ Growth factors correct number of chromatids in both nuclei - Provide instructions for other cells to grow Cyclins and Cyclin-Dependent Kinases (CdK) - Growth factors are proteins that stimulate ○ controls the progress of a cell from one phase to cell division, which have the ability to the next of the next cell cycle activate specific genes to trigger cell ○ These protein fluctuate during the cell cycle due growth to degradation - Some growth factors can also affect the Maturation-Promoting Factor (MPF) growth of other cells ○ A cyclin-CdK complex ○ Example of growth factors: ○ Triggers the cell to pass G2 checkpoints to - Erythropoietin stimulates the production of undergo mitosis cells that become red blood cells - Platelets responsible for blood clotting.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION INTERNAL FACTORS QUALITY CONTROL Come from insider the cell that include several types Systems for interrupting the cell cycle if something of molecules in its cytoplasm goes wrong Kinases and cyclins ○ DNA damage checkpoint ○ Kinase - Happens at G1 checkpoint + S phase + M - An enzyme that transfers a phosphate group phase from one molecule to the target molecules. - P53 gene - tumor suppressor - This mechanism accelerates the energy of ○ Completion of S-Phases the target molecule or changes its shape - Makes sure that there are no okazaki - Kinases that help control cell cycle can be fragments activated by a group of proteins called ○ Spindle Checkpoint cyclins - Assures spindles are properly connected to ○ Cyclins kinetochore - Rapidly destroyed at certain points in the If problem cannot be fixed, the cell signals for cell to allow cells to progress from G1 stage apoptosis to mitosis stage - Cyclins + kinases help cells advance to APOPTOSIS different stages of the cell cycle Apoptosis is a process that occurs in multicellular Cycle Checkpoints - prevents the cell from cells when a cell intentionally “decides” to die. This proceeding to the next stage, until all required often occurs for the greater good of the whole criteria have been met. organism, such as when the cell’s DNA has become THE CELL CYCLE CLOCK / CHECKPOINT damaged and it may become cancerous. 2 Types of Regulatory Molecules, together act as a Apoptosis is referred to as “programmed” cell death checkpoint because it happens due to biochemical instructions ○ Kinases in the cell’s DNA; this is opposed to the process of - Amount doesn’t fluctuate “necrosis,” when a cell dies due to outside trauma - enzymes that phosphorylates molecules or deprivation. - Cyclin dependent kinase (Cdk) – inactive (G1 & G2) until cyclin are present DISORDERS AND DISEASES THAT RESULT FROM ○ Cyclins THE MALFUNCTION OF THE CELL DURING THE CELL - Molecule concentration fluctuates (unlike CYCLE kinase) Cancer - Bonds w/ Kinase and serves a checkpoint ○ A group of diseases that involve in irregular - Cyclin-Cdk complex (MPF M-phase growth and reproduction cells promoting factor) promotes certain activities ○ Cancer occurs when genes involved in the cycle, that eventually lead to the next stage of the specifically with checkpoints are altered cell cycle ○ Transformation - single cell converts to a - Having the minimum concentration of these cancer cell complexes help the cell cycle proceed ○ Benign Tumor - a group of abnormal cells that through the checkpoints does not invade other body systems - not considered cancerous STEPS OF THE CELL CYCLE ○ Metastasis - when cancerous cells break off Sometime after cytokinesis G1 cyclins rise and bind the original tumor and travel to other parts of the to their Cdks (activates Cdks) which signals the cell body to prepare for chromosome replication.– This ○ Malignant Tumor - a tumor that invades body moves cell past G1 checkpoint system by traveling via the bloodstream or the “S” phase promoting factor (SPF) enters the nucleus, lymphatic system prepares the cell to duplicate its DNA and ○ Cancer causes death b/c the cells take over the centrosomes – S phase begins function of organs S-cyclin-Cdk complexes form. They phosphorylate ○ Cancer arises due to damage to genes (90%) or proteins that ensure DNA replication. inheritance (10%).GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION GROWTH FACTORS AND CANCER WHAT CAUSES THESE HITS Growth Factors can create cancers Mutations in cells can be triggered by ○ Proto-Oncogenes ○ Uv radiation - normally activates cell division ○ Chemical exposure growth factor genes ○ Radiation exposure become Oncogenes (cancer-causing) ○ Heat when mutated ○ Cigarette smoke - if switched “ON” can cause cancer ○ Pollution - example: RAS (activates cyclins) ○ Age ○ Tumor Suppressor Genes ○ Genetics - normally inhibits cell division - if switched “OFF” can cause cancer. Why? TUMORS - example: p53 Mass of abnormal cells ○ Benign tumor CANCER & CELL GROWTH - Abnormal cells remain at original site as a Cancer is essentially a failure of cell division control lump ○ Unrestrained uncontrolled cell growth - p53 has halted cell divisions What control is lost - Most do not cause serious problems & can ○ Lose checkpoint stops be removed by surgery ○ Gene p53 plays a key role in G1/S restriction ○ Malignant tumor point - Cells leave original site ○ p53 protein halts cell division if it detects - lose attachment to nearby cells damaged DNA - carried by blood & lymph system to other - stimulates repair enzymes to fix DNA tissues - forces cell into G0 resting stage - start more tumors = metastasis - keeps cell in G1 arrest - impair functions of organs throughout body - causes apoptosis of damaged cell ○ ALL cancers have to shut down p53 activity GENETIC DISORDERS ASSOCIATED WITH MEIOSIS ○ Inhibits blood vessel growth in tumors Down syndrome (Trisomy 21) (angiogenesis) ○ The twenty-first chromosome has three instead of two chromosomes. DEVELOPMENT OF CANCER ○ They are born with a number of birth defects in Cancer develops only after a cell experiences 6 key the heart, intestines, and breathing. Delayed mutation hits mental development is also observed. Gradual ○ Unlimited growth decline in mental abilities around the age of 50 - Turn on growth promoter genes are also experienced. ○ Ignore checkpoint ○ An affected offspring has physical attributes of - Turn off tumor suppressor genes short stature, round head, flat face, slanting ○ Escape apoptosis eyes, stubby fingers, wide gap between the first - Turn off suicide genes and second toes, short neck, short arms, and ○ Immortality = unlimited divisions short legs - turn on chromosome maintenance genes Turner Syndrome (45, XO) ○ Promotes blood vessel growth ○ A chromosomal condition seen in female - turn on blood vessel growth genes individuals that have small and underdeveloped ○ Overcome anchor & density dependence ovaries, uterus, and oviducts. - turn off touch-sensor gene ○ Affected individuals have short, broad chest, webbed neck, and puffiness or swelling of hands and feet. They have normal intelligence and can live fairly normal lives.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION Klinefelter Syndrome (47, XXY) CHAPTER 3: CELL TRANSPORT MECHANISM ○ Some variants of this chromosomal disorder are 48, XXXY or 49 XXXXY that are associated with I. TRANSPORT severe forms of abnormality. Is the movement of substances into and out of a ○ Affected males have big hands and feet, and cell unusually long arms and legs. They may have Can either be active or passive delayed speech and language development, ○ Active transport - requires energy in the form of and learning disabilities. ATP ○ Chromosomal abnormality affecting the physical ○ Passive transport - requires no energy and cognitive development of males. ○ Affected individuals have underdeveloped CELL BOUNDARIES prostate gland and testis, thus, there is Every living cell exists in a liquid environment. shortage of testosterone production. This leads There is liquid on the inside and outside of a cell. to delayed or incomplete puberty. One of the most important functions of the cell ○ Affected individuals have lack of facial and body membrane is to regulate the movement of hair, breast enlargement, and unusually small molecules from one side membrane to the other penis. side. Trisomy X (47, XXX) ○ It affects one in 1000 females with abnormal SEMI-PERMEABLE MEMBRANE presence of an extra X chromosome. Smaller molecules can pass through. ERRORS SOMETIMES OCCUR IN MEIOSIS Larger molecules cannot. If chromosomes fail to separate during anaphase I or anaphase II, then abnormal gametes form. PASSIVE TRANSPORT If an abnormal gamete participates in fertilization, a Particles moving from high to low concentration zygote with an improper chromosome number is Doesn’t require energy produced. Diffusion Individuals with missing chromosomes often cease ○ Diffusion is a passive process which means no developing before birth. An extra chromosome energy is used to make the molecules move, they often causes fewer problems than a missing have a natural kinetic energy chromosome. ○ The movement of molecules down a An extra copy of a chromosome—a concentration gradient from a region of high trisomy—causes genetic disorders such as Down concentration to a region of low concentration syndrome. until equilibrium is reached Extra or missing sex chromosomes cause sex ○ Facilitated Diffusion disorders. - Requires hydrophilic protein channel that The age of the mother can also add up to the will passively transport specific substances equation. The older the woman is during pregnancy, across the membrane and to move polar or the older is the age of her eggs because she was charged substances across the born with all the eggs she will ever have. hydrophobic regions of the membrane. ○ Example: A woman of 45 years of age during - Molecules will randomly move through the pregnancy has a 45-year-old-eggs as well. pores in Channel Proteins. Errors in meiosis have higher risk due to the aging - channel transports single ions: Na+, K+, process. Incorrect number of chromosomes were Ca2+, Cl- also found by fertility doctors to be connected with - Types of Transport Proteins aging eggs. Channel proteins are embedded in the cell membrane & have a pore for materials to cross Carrier proteins can change shape to move material from one side of the membrane to the other.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION - Some carrier proteins do not extend Water is attracted to the solute inside through the membrane. the cell. - They bond and drag molecules through the The solute concentration is greater lipid bilayer and release them on the inside the cell than outside, therefore opposite side. water will flow into the cell. - Significance - Moves glucose, sodium ions, Results to turgor pressure in plant cells and potassium ions in and out of the cell Cytolysis membrane ★ The destruction of a cell. ○ Simple Diffusion ★ Cells swell and burst - Does not involve protein channels - Hypertonic - A solution whose solute - Example: Oxygen or water diffusing into a concentration is higher than the solute cell and carbon dioxide diffusing out. concentration inside a cell. - The one found in the glomerulus of the human The water is going out of the cell. kidney, where solutes dissolved in the blood The solute concentration is greater diffuse into Bowman’s capsule of the outside the cell, therefore water will flow nephron. outside the cell. - Countercurrent Exchange Plasmolysis A special case of simple diffusion ★ The shrinking of a cell The flow of adjacent fluids in opposite ★ Cells shrink and shrivel directions that maximizes the role of Aquaporins simple diffusion ○ Are special water channel proteins found in Fish gills - blood flows toward the head certain cells that facilitate the diffusion of in the gills, while water flows over the massive amounts of water across a cell gills in the opposite direction. membrane. Osmosis ○ These channels do not affect the direction of ○ Diffusion of water across a membrane water flow, but, rather, the rate at which water ○ Water is attracted to solutes (like salt) so it will diffuses down in a gradient also travel to areas of low solute concentration to high solute concentration. ACTIVE TRANSPORT ○ Osmotic Potential Requires energy or ATP - the tendency of water to move across a Moves materials from low to high concentration permeable membrane into a solution Against concentration gradient ○ Diffusion of water across a membrane Examples: Pumping Na+ (sodium ions) out and K+ ○ High water concentration -> Low water (potassium ions) in — against concentration concentration gradients. ○ Low solute concentration -> High solute Sodium-Potassium Pump concentration ○ 3 Na+ pumped in for every 2 K+ pumped out; ○ Cells in Solutions creates a membrane potential. - Isotonic - A solution whose solute Exocytosis concentration is the same as the solute ○ Type of active transport concentration inside the cell. ○ Moving things out The cell is at equilibrium ○ Molecules are moved out of the cell by vesicles Water will flow in both directions that fuse with the plasma membrane. outside and inside the cell. ○ This is how many hormones are secreted and The solute and water concentrations how nerve cells communicate with each other. are the same inside and outside the cell. Endocytosis - Hypotonic - A solution whose solute ○ Large molecules move materials into the cell by concentration is lower than the solute one of three forms of endocytosis. concentration inside a cell The water is going inside the cell..GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION - Pinocytosis POLYMERS Most common form of endocytosis. Condensation Polymerization Takes in dissolved molecules as a ○ (aka dehydration synthesis) removes an OH and vesicle. H during synthesis of a new molecule Cell forms an invagination - Polymerization Diagram Materials dissolve in water to be Water is formed and ATP is required brought into cell Breaking down Polymers Called “Cell Drinking” ○ Hydrolysis breaks a covalent bond by adding OH - Receptor-mediated endocytosis and H from a water molecule Some integral proteins have receptors - Hydrolysis Diagram on their surface to recognize & take in Water is required hormones, cholesterol, etc. - Phagocytosis II. TYPES OF BIOMOLECULES Used to engulf large particles such as food, bacteria, etc. into vesicles CARBOHYDRATES Called “Cell Eating” Monomer: Saccharide Capture of a parasite by membrane Carbohydrate means hydrated carbon extensions of an immune system cell Composing elements C, H, O Hydrogen and Oxygen are in a ratio of 2:1 CHAPTER 4: STRUCTURES AND FUNCTIONS OF Can be simple monomers like glucose BIOLOGICAL MOLECULES Can be complex monomers like cellulose The more complex the structure is, the more difficult I. BIOMOLECULES it is for our body to digest the substance and the Molecules that make up living things longer we feel satiated. They are very large molecules of many atoms Functions: covalently bonded together ○ Store energy All living things are mostly made of 4 types of ○ Provide some structure molecules called biomolecules Made of many sugars bonded together in a long Energy is stored in the covalent bonds of these chain molecules. When we eat, we get energy to live as ○ Starch, Cellulose, Glycogen chemical reactions within our bodies break these Monomer: Sugar bonds. Polymer: Starch Our bodies can then use these parts of these large Cell structure: Starch grains in chloroplasts molecules to build molecules that build our bodies. Sugars ○ Monosaccharides ORGANIC COMPOUNDS - C6H12O6 Most biomolecules are organic - Fructose - Fruit sugar This means they are based on carbon and include - Galactose - Less sweet than fructose and hydrogen. glucose Includes carbohydrates, lipids, proteins, and - Glucose - Dextrose or blood sugar nucleic acids. - Importance: Also includes vitamins (fat-soluble vitamins) Energy source: used as a reactant in respiration MACROMOLECULES Monomer Unit: monosaccharides Large biomolecules Used to form: Dimers (disaccharides) Many of these are polymers and Polymers (polysaccharides) ○ Polymers: Long molecules built by linking ○ Disaccharide another small similar subunits (monomers) - Lactose: glucose + galactose (milk sugar) - Maltose: glucose + glucose (cereals, grain) - Sucrose: glucose + fructose (table sugar).GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION - Condensation to form disaccharides Made by Ribosomes (produces H2O) ○ Amino acids are joined together by peptide - Importance: bonds following a sequence dictated by the DNA Energy storage: sucrose is a store of (DNA > Transcription > mRNA > Translation > energy in sugarcane and sugar beets Polypeptide/Protein) Energy transport: carbohydrate is Amino Acids transported in plants as sucrose ○ Building blocks of proteins Polysaccharide ○ Contain nitrogen ○ Complex sugars made up of chains and/or ○ 20 naturally occurring and encoded by DNA branches of monosaccharides. ○ R group determines chemical properties, any ○ Acts as storage and as structural molecule side group - Starch - plants carbohydrates that is ○ About half can be made by our body and about composed of glucose molecules (potato half needs to be consumed (Between 8-10 are tubers, cassava, corn, cereals) essential) - Glycogen - animal carbohydrates storage. ○ Components: Amino group, Carboxyl Group, R Can easily broken down into glucose ○ Amino acids are compounds which contain both molecules when needed. Insoluble in water an amino group and a carboxylic group and forms a highly compact shape ○ Proteins are made up of 20 essential amino - Cellulose - found in cell wall of plants and acids highly insoluble; for plant protection and ○ These essential amino acids polymerize in a support condensation polymerization to yield your ○ Structural Carbohydrates protein. - Chitin - arthropod exoskeleton and fungal cell wall (modified form of cellulose) Role of Carbohydrates: ○ An essential part of our diet ○ The body uses carbohydrates directly from monosaccharide glucose ○ Energy is derived from glucose by splitting of glucose molecules into smaller compounds and oxidizing to form water PROTEIN C,H,O,N and some have S (a few might also have P due to addition of P in the modification process but P is not a component of amino acids. Monomer: Amino acids Insulin: C254H377N65O76S6 Folding of polypeptides to form proteins Found in living organisms ○ Shape of a proteins are important because this Greek word “proteos” = first place determines how they interact with other Functions: molecules ○ Build muscle, bone, structural support of the ○ This determines their particular function cell - Primary structure: straight chains of amino ○ Function as enzymes to speed chemical acids reactions within the body - Secondary structure: amino acids bonded by ○ Functions as pigments and steroid hormones peptide bond Made of many amino acids bonded together in a - Tertiary structure: 3d diagram of polypeptide long chain - Quaternary structure: system or structure of Monomer: Amino acid protein Polymer: Protein chain Cell structure: Muscle fiber.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION 7 Major Classes of Proteins Functions: ○ Structural protein: fiber that makes up the ○ Main function is to store and produce energy tendons and ligaments, cell walls ○ Insulating materials to prevent heat loss - (Structural: Keratin, Histone Protein) ○ Serve as solvent for fat-soluble vitamins and ○ Contractile protein: provide muscular movement hormones - (Contractile: Actin and Myosin) ○ Prevent water loss in the skin ○ Storage protein: main substance in egg white ○ Form cell membranes ○ Defensive protein: antibodies Can be Saturated or Unsaturated depending on the - (Immunity) type of bond ○ Transport protein: an example is hemoglobin Monomers: fatty acids and glycerol - (Transport: Protein Channels or Carrier ○ Glycerol: an alcohol with three oxygen groups Proteins) ○ Fatty Acids: long hydrocarbon chains ○ Signal protein: hormones that coordinate body All lipids repel water, due to how hydrophobic they activities are. They do not bond to water molecules - (Regulation: Insulin) Subunit structure: fatty acid ○ Enzyme: increase rate of chemical reactions, Molecule: fat molecule chemical catalyst Cell: adipose cells - (Catalysts: Lipase) Lipid Structure ○ Muscle contraction and relaxation, Surface ○ Composed of a glycerol molecule attached with receptors, Secondary Energy source fatty acids Amino Acids ○ Triglyceride & phospholipid ○ 9 essential amino acids; must be consumed ○ Some lipids have a four ringed structure ○ 12 non essential amino acids - E.g., cholesterol and other lipids that are ○ Amino acids are linked by peptide bond (aka. derived from cholesterol Amide bond) Steroid Hormones ○ Covalent bond: carboxyl and amine group ○ Progesterone (menstrual cycle and with ○ Water - by product differentiation factor for mammary glands ) Roles of Protein ○ Aldosterone (raises blood pressure and fluid ○ Main source of nitrogen in our body volume, increases Na+ uptake) ○ Serves to build structures in the body ○ Testosterone (secondary male sex ○ Biochemical reactions characteristics) ○ Carrier of other materials ○ Estradiol (secondary female sex characteristics) ○ Immune system ○ Cortisol (stress adaptation, elevates blood ○ Keep the acid-base balanced in our body in pressure and Na+ uptake, numerous effects on ranges that allow us to stay alive the immune system) 2 rings = unsaturated fat LIPIDS Saturated Fats Composing elements C, H, O ○ Have no double bonds between carbon atoms Monomer: 1 Glycerol & 3 Fatty Acid Chains (have maximum number of hydrogen atoms) Lipids are loosely defined as groups of organic ○ Straight structure molecules that are insoluble in water. Their chemical ○ Unhealthy. Fats usually from animal sources formula varies considerably. ○ Solid at room temperature (20°C) Include: Unsaturated Fats ○ Fats ○ Some carbon atoms that are double bonded ○ Oils (not fully hydrogenated) ○ Waxes ○ Kinked in shape ○ Phospholipids ○ Healthy ○ Steroids: sex hormones and cholesterol ○ From plant sources ○ Some vitamins ○ Liquid a room temperature (20°C) ○ Glycolipids (lipids with carbohydrates attached) ○ Monounsaturated Fats: one double bond Greek word “lipos” = fat.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION ○ Polyunsaturated Fats: more than one double NUCLEIC ACID bond in the hydrocarbon chain Biomolecules that contain the blueprint for making ○ Ex: proteins - Palmitoleic acid (Mono): adipose tissue, all Transmits genetic info to the next generation tissues, abundant in liver Direct the production of proteins - Oleic acid (Mono): olive or oil, omega-9 fatty Monomers: Sugar (Deoxyribose, Ribose), acid, animals and vegetables Phosphate Group, Nitrogenous Base Pair - Linoleic acid (Poly): omega-6 fatty acid Includes: Trans Fat ○ DNA ○ Not essential for the body ○ RNA ○ Does not promote good health Composing elements: C, H, O, P, N ○ Check nutritional facts Deoxyribonucleic Acid (Deoxyribose) Cis Fat ○ Encodes information used to assemble ○ 2 hydrogen atoms adjacent to a double bond proteins are on the same side Ribonucleic Acid (Ribose) Fats ○ Reads DNA-encoded information to direct ○ Fats are a specific type of lipid. protein synthesis ○ Chemically, all fats are triglycerides – they have Made of many nucleotides bonded together in long three fatty acids bonded to one glycerol molecule. chain Detection of Lipids Monomer: Nucleotide ○ Oily and fatty foods tend to leave stains upon Polymer: DNA Strand contact Cell structure: Chromosome ○ This is why we can use brown paper to detect Nucleotide Parts: fats ○ 5-carbon sugar (pentagon) ○ We can use ethanol, which dissolves lipids ○ Phosphate group (circle) ○ The dissolved fats are then diluted with water. ○ Nitrogenous base (rectangle) Since water and lipids don’t mix, the lipids ○ Nucleoside: the sugar and the base without the come out of solution phosphate ○ This creates an emulsion — a milky, cloudy Nucleotides (C - G, A - T): liquid ○ Cytosine Examples of Lipids ○ Adenine ○ Waxes (protective cuticle, ear wax) ○ Thymine: replaced by Uracil in RNA ○ Phospholipids (cell membrane) ○ Guanine ○ Triglycerides The fifth carbon of the sugar is bonded to a phosphate ○ Sphingolipids (nerves, brain, lungs) group. Thus, we say that this is the 5’ end. The third Importance of Lipids carbon of the sugar is bonded to an OH group. This is ○ Used to store energy (approx 36 kj/gram) called the 3’ end. ○ An important structural component of membranes Importance: ○ Acts as a schlock absorber and good insulator ○ Nucleic acid are blueprints for proteins ○ Waterproofing of some surfaces - Proteins are made from these templates ○ Transmission of chemical messages via hormones ○ DNA can be passed down leading to offspring to Triglycerides are not polymers have some traits - Hereditary ○ RNA cannot be passed down to offspring.GENERAL BIOLOGY 1.2nd Trimester | CELLS, BIOLOGICAL MOLECULES, & ENERGY TRANSFORMATION CHAPTER 5: ENERGY TRANSFER ADP-ATP CYCLE Cells break phosphate bonds betweens the last two I. CELL RESPIRATION phosphate groups in a molecule of ATP as needed Cell respiration is the means by which cells extract to supply energy for most cellular functions, when energy stored in food and transfer that energy to this happens a molecule of ADP (adenosine molecules of ATP diphosphate) and a phosphate become available for Energy that is temporarily stored in molecules of ATP reuse. is instantly available for every cellular activity such as: When any of the phosphate bonds are broken or ○ Neurons sending and receiving information formed, energy is involved. ○ Muscle contraction / movement ○ Energy is released each time a phosphate is ○ Movement of cilia and flagella removed from the molecule. ○ Protein synthesis ○ Energy is stored each time a phosphate The process of photosynthesis and cellular respiration attaches to the molecule. are said to happen simultaneously in plants To constantly supply the cell with energy, the ADP is recycled, creating more ATP which carries much ADP AND ATP more energy than ADP. ATP: Adenosine Triphosphate ○ Is the energy currency of all cells, including STEPS IN THE ADP-ATP CYCLE plants and animals. It supplies you with energy To supply cells with energy, a “high energy” bond in ○ ATP is a type of nucleic acid (like DNA and RNA) ATP is broken. ADP is formed and a phosphate is ○ ATP contains high energy phosphate bonds that released back into the cytoplasm store and release energy. ○ Where does ATP come from? ATP → ADP + phosphate + energy - ATP comes indirectly from the food that we eat. As the cell requires more energy, ADP becomes ATP - Molecules of carbohydrates (glucose) and when a free phosphate attaches to the ADP lipids are broken down through the process molecule. Then energy is needed to create an ATP of cellular respiration to produce ATP molecule much less than the amount of energy ○ An ATP molecules is composed of the following produced when the bond is broken. - A Nitrogenous Base - Adenine - A Sugar - Ribose ADP + phosphate + energy → ATP - Three phosphate groups ○ Autotrophs and heterotrophs share the same HOW IS THE BOND BROKEN energy to drive their cellular processes Hydrolysis (Adding H20) (ATP-ADP) - Autotrophs have the capacity to release the ○ Assisted by the enzyme ATPase (needed to energy from the same molecule that they speed up separation)