Biology Chapter 7 Quiz: Macromolecules & Viruses

Test #1

• Biology is the science that studies living organisms and their interactions with other environments.
• Peer review ensures scientific research is original, logical, and thorough.
• Inductive reasoning takes observations to make a general conclusion.
• Deductive reasoning uses a general principle to predict specific results.
• The scientific method typically starts with an observation and a question, followed by a hypothesis and testing of that hypothesis.
• The controlled group is the same as the experimental group but not given the manipulation.
• Variables are any part of an experiment that can change.
• A hypothesis should be falsifiable.
• Basic science seeks to expand knowledge, while applied science seeks to solve real-world problems.
• Properties of life include: order, sensitivity, reproduction, adaptation, growth, regulation, energy processing and evolution.

Properties of Life

• Organisms share several key characteristics: order, sensitivity, reproduction, adaptation, growth, regulation, energy processing, and evolution.
• Order - organisms have coordinated structures
• Sensitivity - Organisms respond to stimuli
• Reproduction - Organisms reproduce by duplicating DNA
• Adaptation - Living organisms exhibit a fit to their environment
• Growth and development - Genes provide instructions for cellular growth and development
• Regulation or homeostasis - mechanisms coordinate internal functions and environmental stresses. Like proper temperature, PH and chemical concentrations
• Energy processing - All organisms use a source of energy for essential activities. Some capture energy from the sun and others use chemical energy
• Evolution - Diversity of life = result of mutations & adaptations to changing environments, which are a consequence of evolution by natural selection

Levels of Organization of Living Things

• Atom is the smallest and most fundamental unit of matter.
• Consist of a nucleus surrounded by electrons.
• A molecule is a chemical structure consisting of 2 or more atoms. Any biologically important molecules are macromolecules (ex. DNA)
• A polymer is a large molecule made by combining monomers.
• Organelles are small structures inside the cell (e.g., mitochondria, chloroplast)
• Prokaryotes - single-celled organisms without a nucleus
• Eukaryotes - (e.g., animals, plants, fungi) have membrane-bound organelles and nucleus
• Organisms are an individual living entity
• Community = all populations living in a particular area
• Ecosystem = all living & nonliving parts in an area
• Biosphere = collection of all ecosystems

The Diversity of Life

• Evolution is the process of gradual change in a population or species over time.
• The phylogenetic tree of life summarizes the evolution of various life forms.
• Diagrams show evolutionary relationships

The Chemical Foundation Of Life

• Matter is any substance that occupies and has space and mass.
• Elements are unique forms of matter with specific chemical and physical properties that cannot break down into simpler substances.
• The four main elements for living things are oxygen, carbon, hydrogen, and nitrogen.
• Atoms contain a nucleus with protons and neutrons. Electrons orbit the nucleus.
• Atomic number = number of protons
• Mass number = number of protons + neutrons
• Isotopes have the same number of protons, but a different number of neutrons.
• Chemical reactions occur when atoms bond to form molecules or when bonds break apart.
• Compounds contain atoms of more than one element

Bonds and Interactions

• Ionic bonds form between ions with opposite charges.
• Covalent bonds form when atoms share electrons. Polar covalent bonds are when atoms share electrons unevenly and nonpolar when they are equal.
• Hydrogen bonds are weak attractions that frequently occur in polar substances, like water.
• Van der Waals interactions are very weak attractions between molecules.

Water

• Water is a polar molecule, with partial charges on the hydrogen and oxygen atoms.
• Waters properties are key to life's processes
  • High heat capacity
  • High heat of vaporization
  • Good solvent
  • Cohesion
  • Adhesion
  • pH, a measure of hydrogen ion concentration, is vital in biological systems.
• Buffers moderate pH changes.
• Acids increase H+ concentration. Bases increase OH- concentration.

The Diversity of Organic Molecules

• Four major categories of organic molecules are carbohydrates, lipids, proteins and nucleic acids. They consist entirely or predominantly of carbon, hydrogen and oxygen
• Each type is a polymer - composed of monomers (repeating units)
• Carbohydrates: often produce energy
• Monosaccharides: simple sugars
• Disaccharides: two monosaccharides
• Polysaccharides: multiple monosaccharides (e.g., starch, glycogen, cellulose)
• Lipids: many functions including energy storage, insulation & hormones
• Fats and oils: Triglycerols (glycerol + 3 fatty acids)
• Phospholipids: form cell membranes
• Steroids: chemical messengers (e.g., cholesterol, hormones)
• Proteins: crucial functions including catalysis, structural support transport, defense, and signaling
• Amino acids form proteins
• Polypeptides many amino acids form a chain
• Proteins complex structures
• Nucleic Acids: DNA and RNA store and transmit genetic information
• Nucleotides form nucleic acids

Synthesis and Decomposition

• Macromolecules are formed when monomers combine through dehydration
• reactions. These reactions involve the loss of water molecules to form new bonds
• Hydrolysis reactions break down polymers by adding water to break up the bonds

Chapter 3 Biological Macromolecules

• Macromolecules
  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids

Chapter 5 Plasma Membranes

• The Plasma Membrane: is a phospholipid bilayer with embedded proteins that separates the cell from its surroundings. It selectively regulates the passage of substances.
• Phospholipids: The primary component of the plasma membrane. Made up of two fatty acid chains attached to a glycerol backbone and a phosphate group.
• Proteins: Integral (embedded) and peripheral (attached) proteins facilitate cell signaling and transport.
• Cholesterol: Inserts between the phospholipids and helps maintain membrane fluidity.
• Glycoproteins and Glycolipids: contribute to cell recognition and cell-cell interactions
• Fluid Mosaic Model: The membrane is fluid and dynamic, and proteins and lipids are embedded in it.

Passive Transport

• Diffusion is the random movement of materials from an area of high concentration to an area of low concentration across the membrane.
• Facilitated diffusion is driven by a concentration gradient. Integral proteins help to transport molecules across the cell membrane
• Osmosis is the facilitated diffusion of water across a semipermeable membrane.
• Hypotonic: Solution has less solute concentration than needed to prevent water entering cell
• Isotonic: Solution that has equal solute concentrations compared to the concentration needed in the cell
• Hypertonic: Solution that has more solute concentration than needed to prevent water leaving the cell

Active Transport

• Active transports moves molecules against the concentration gradient from an area of low concentration to an area of high concentration and requires ATP.
• Endocytosis and Exocytosis: Large molecules, such as proteins or entire cells are transported into or out of the cell.
  • Phagocytosis - 'cell eating'
  • Pinocytosis - 'cell drinking'
  • Receptor-mediated endocytosis - specific uptake (by binding to the receptor).

Chapter 4: Cell Structure

• Cell theory - all living things are composed of cells
• Cells - basic building blocks of life
• Microscopy: Different types of microscopes used to visualize cells.
• Prokaryotic cells - Single-celled organisms lacking a nucleus (bacteria).
• Eukaryotic cells - Possessing organelles, including a nucleus

Bacterial Cells

• Prokaryotic DNA is found in the nucleoid region.
• Cell walls of prokaryotes are composed primarily of peptidoglycan.
• Some prokaryotes have a capsule outside the cell wall for protection.
• Other structures, like pili or flagella, may be present for adhesion or movement.

Eukaryotic Cells

• Nucleus: Contains the cell's DNA and controls functions.
• Cytoplasm: Jelly-like substance filling the cell, holds organelles in place.
• Endoplasmic reticulum (ER): A network of interconnected membranes that either has ribosomes on its surface (Rough ER) to make proteins or smooth ER without ribosomes to make lipids.
• Golgi Apparatus: Sorts, modifies, and packages proteins & lipids.
• Mitochondria: Site of cellular respiration and energy production
• Ribosomes: Site of protein synthesis in all organisms.
• Vacuoles and Vesicles: Membrane-bound sacs involved in storage and transport
• Lysosome: Contains enzymes to digest waste.
• Cytoskeleton: Filamentous proteins that give support and shape to cells

The Endomembrane System

• The endomembrane system is an interconnected network of membranes that modify, sort, and transport materials within the cell. This consists of the nuclear envelope, endoplasmic reticulum, Golgi apparatus and vesicles.

Cell Structures and their Function

• Cell wall- provides structural support.
• Plasma membrane- selectively regulates materials allowed to enter and exit the cell.
• Cytoskeleton- consists of microtubules, microfilaments and intermediate filaments; give support and shape to the cell.
• Cytoplasm- surrounds the nucleus and contains organelles.
• Nucleus- contains the DNA
• Nucleolus- where rRNA is made.
• Ribosomes- sites of protein synthesis.
• Peroxisomes- metabolically active in cells
• Vacuoles and vesicles- involved in transporting molecules.
• Mitochondria- produces energy
• Endoplasmic reticulum- protein and lipid synthesis and transport
• Golgi apparatus- modifies, sorts and packages proteins and lipids
• Lysosomes- involved in digestion in cells

Chapter 15 Genes and Proteins

• The central dogma DNA codes for RNA and RNA codes for protein.
• Chromosome- an ordered structure of DNA in eukaryotic cells
• Genes - particular DNA sequence which codes for a specific trait
• Chromosomes are made primarily of DNA
• Chromatin is unwound DNA.
• Nucleotides are the building blocks of DNA and RNA, consisting of a sugar, base, and phosphate

Chapter 15 Genes and Proteins

• DNA encodes the sequence of RNA. RNA carries the coded message to the ribosome where protein synthesis takes place.
• RNA is involved in the conversion of the sequence encoded in DNA into a form that directs protein synthesis.

Chapter 20 Phylogenies and the History of Life

• Phylogenetic trees: Diagrams to show evolutionary relationships of living organisms.
• Organisms branch out on the trees, the more the newer the species.

Chapter 16 Gene Expression

• Gene expression - The process of turning on a gene to produce RNA and protein.
• Prokaryotic gene regulation - Regulation of genes during transcription at the level of transcription is most prevalent in prokaryotes as it involves an operon system, which is an organized set of genes.
• Eukaryotic gene regulation- Gene regulation can occur at various levels, including transcription, RNA processing, translation, and post-translational modifications
• Operons - A series of genes grouped together under a single promoter

Chapter 7 Metabolism

• Energy production in a cell - Many chemical pathway occur at the same time
• Photosynthesis - Anabolic reaction making glucose
• Cell respiration - Catabolic reaction breaking down glucose
• Metabolism - All of the chemical reactions occurring in a cell

Chapter 10 Cell Reproduction

• The cell cycle is the sequence of events in a cell leading up to and including cell division
• Interphase - G1 (growth), S (DNA synthesis), G2 (growth).
• Mitosis- the process of nuclear division
• Prophase, prometaphase, metaphase, anaphase, telophase.
• Cytokinesis - division of the rest of the cells components
• The events that occur during mitosis and cytokinesis divide the chromosomes and cytoplasm to make new, identical cells.
• Meiosis - A specialized type of eukaryotic cell division that produces haploid gametes (sperm and egg cells)

Chapter 21 Viruses

• Viruses are small bundles of nucleic acids wrapped in proteins
• They vary in structure, how they replicate & which hosts they infect
• Morphological types of viruses include helical, icosahedral envelope and complex types

Chapter 42 The Immune System

• The human immune system can be broken down into two main categories
• Non-specific: The body's first line of defense against invaders
• Specific defenses: The body's second line of defense against invaders
• Barrier defenses: mucous membranes, Skin, enzymes or acidic secretions, and inflammation

Chapter 10 Cell Reproduction

• Mitosis- used for growth, repair, and asexual reproduction of somatic cells; divides the nucleus and generates two identical cells, beginning from an actively growing cell
• Mitosis is a sequence of events leading to dividing of the nucleus and cell
• Meiosis is a specialized type of cell division (used to make gametes) that generates four haploid cells and reduces the chromosome number by half
• The cell cycle - A series of events that cells go through as they grow and divide

Important Cellular Processes (Overview)

• Protein Synthesis: Transcription (DNA → RNA) and translation (RNA → protein).
• Cellular Respiration: Breakdown of glucose to produce energy (ATP).
• Cell Cycle: Growth, DNA replication, and division of cells
• Gene regulation: Mechanisms to regulate the production of proteins.