Concept 1 Notes - Biology Review PDF

 Overview Biology is the study of life. All living things (organisms) are: – Made of cells – Respond to stimuli – Able to grow and reproduce – Use energy (have a metabolism) The sum of all the biochemical processes in the body – Contain DNA or RNA as geneti...

 Overview Biology is the study of life. All living things (organisms) are: – Made of cells – Respond to stimuli – Able to grow and reproduce – Use energy (have a metabolism) The sum of all the biochemical processes in the body – Contain DNA or RNA as genetic material – Adapt to their environment  Cells Cells are the most basic structural and functional unit of life. – It is the smallest part of an organism that is still capable of all of life’s processes Cells are very diverse. – There are prokaryotic and eukaryotic cells. – Eukaryotic cells differ between plants, animals, fungi, and protista. – Even within humans there are believed to be more than 200 types of specialized cells! Cells are made up of organelles. – Specialized structures within the cell that work together to help the cell function.  Cytoplasm Structure Jelly-like fluid inside of cells Mainly made up of water Function Holds everything in place  Cell (Plasma) Membrane Structure A selectively permeable barrier (known as the phospholipid bilayer) – 2 layers of phospholipids with hydrophilic (likes water) heads and hydrophobic (dislikes water) tails – Carbohydrates are embedded throughout to provide structure – Proteins are embedded to aid in transporting nutrients and signals  Cell (Plasma) Membrane Draw and Label the parts of a phospholipid in your notes! Polar Structure hydrophilic head Made of phospholipids – Phosphate “head” – 2 fatty acid chain “tails” Arranged in a bilayer (2 layers) – Polar heads = hydrophilic, Nonpolar meaning they “like water” hydrophobic – Nonpolar tails = tails hydrophobic, meaning they are “afraid of water”  Cell (Plasma) Membrane Function Controls what goes in and out of the cell – The arrangement of the phospholipids allows some molecules to easily pass through and others to require more effort. CAN PASS EASILY = Small, non- polar, hydrophobic, neutral molecules and water (even though H2O is polar it is reallyyyy tiny!) CANNOT PASS EASILY = Polar molecules (must go through protein channels) and large molecules (must use vesicles) Critical for communication and maintaining a stable internal environment (homeostasis)  Cytoskeleton Structure Threadlike fibers Made of proteins 3 types: microtubules, intermediate filaments, and microfilaments Function Support, maintain shape, motility, and regulate biochemical activities  Centrioles An organelle associated with the cytoskeleton Structure Made of microtubules Microtubules “grow” out of 2 centrioles are referred together as a centrosome Function Appear during cell division Help cell divide by pulling chromosomes apart during Anaphase  Cilia and Flagella An organelle associated with the cytoskeleton Structure Cilia: shorter, more numerous, like tiny oars – Similar projections that are short and numerous but don’t move are called microvilli Flagella: longer, fewer (1-3) Function Cilia: move fluid across cell’s surface Flagella: move entire cell through extracellular fluid This image shows This image sperm cells, shows with microvilli on flagellum the outside tails, of a human swimming body cell towards an egg cell Structure Nucleus Contains genetic material (DNA) – When it appears threadlike (as pictured below), it is considered to be chromatin – Chromatin condenses into 46 chromosomes (which appear rodlike) in body cells Remember sex cells, like egg and sperm, only have 23 chromosomes – Genes are sections of chromosomes that code for proteins (which then do most of the work in the cell) Surrounded by a nuclear envelope/membrane with pores that control what goes in and out Nucleolus is in the center Function Protects the DNA that controls the activities of the cell Nucleolus is where ribosomes are formed  Ribosomes Structure Made of proteins and rRNA Located on Rough ER and floating in cytoplasm Function Make proteins!!! – Ribosomes on the Rough ER make proteins to export from the cell – Ribosomes floating in the cytoplasm produce proteins to use within the cell  Rough ER (Endoplasmic Reticulum) Structure Has ribosomes on surface Hugs the nucleus Network of membranes and sacs Function Makes proteins! Package them for secretion Send transport vesicles to the Golgi apparatus – Vesicles: like mini- carts that transport proteins around and out of the cell  Smooth ER (Endoplasmic Reticulum) Structure No ribosomes on surface Attached to Rough ER Network of membranes and sacs Function Makes lipids (membrane) Chemically modifies small molecules Site of glycogen degradation Stores Ca+2 (a trigger for many cell responses)  Golgi apparatus Structure Folded/flattened membrane sacs Function Gets vesicles of protein from the Rough ER and further processes, modifies, packages and sorts them for transport – Vesicles: like mini- carts that transport proteins around and out of the cell Processes, sorts, and ships proteins where needed  Lysosomes Structure Contain hydrolytic enzymes for breaking stuff down Function Breakdown dead stuff (food, bacteria, old parts of cell, etc.) Can do programmed cell death (apoptosis)  Vacuoles Structure Smaller and (can be) more numerous in animal cells Function Storage (water, nutrients, waste, etc.)  Mitochondria Structure Two parts: folded inner membrane (cristae) and enzyme-packed fluid (matrix) Function Where cellular respiration happens – Breaks down chemical energy in food to release it as usable energy in the form of ATP  Practice Time! 3 4 2 5 1 6 7 12 11 8 10 9  Living Tissue Composition Cells are organized into tissues, which work together for a common function. About 70% of our Living Tissue Composition living tissue is made of water Around 26% is composed of Macromolecules macromolecules – Key large biological Water molecules that make up all living things The rest is ions and other small molecules  Macromolecules Living Tissue Composition Macromolecule Proportions Carbohydrates Macro- molecules Lipids Water Proteins Macromolecules are larger molecules (polymers) made of smaller molecules (monomers) typically linked together through covalent bonds. Each macromolecule plays a critical role in organisms with regards to running the body, containing information for how to run the body, and providing the energy needed to do so.  Macromolecules Nucleotides Informational molecules Nucleic DNA A, T, C, G make up Blueprint for life and Acids RNA Stores, transmits, and expresses our A, U, C, G make up genetic information Fats, oils, Energy storage molecules Fatty acids and Lipids glycerol steroids, Also used structurally in the cell membrane, phospholipids for protection, and insulation Energy storage molecules Glucose, Carbohydrates Monosaccharides fructose, Also used structurally, to transport stored glycogen energy, and for recognition in signaling pathways Enzymes, EVERYTHING ELSE molecules hormones, Proteins Amino Acids motor proteins, Enzymes, signaling, receptors, structural, transport regulatory, contractile, protection against disease, transport, storage, etc. proteins, etc.  Macromolecules A few important highlights Your DNA, organized in 46 chromosomes and thousands of genes, provides the instructions for making proteins, which run your body. 1 gene gets transcribed into a copy of mRNA, which leaves the nucleus and heads to a ribosome to be translated and then modified into a functioning protein. This process is highly regulated!! DNA is unzipped and a single stranded copy of mRNA is made from one side. tRNA molecules transfer corresponding amino acids to the ribosome, which are bonded together to form the polypeptide chain. This chain will then undergo folding until it has all four levels of protein structure and is ready to be transported where it is needed to be used.  Macromolecules A few important highlights Enzymes are mostly proteins that are biological catalysts. – Catalysts speed up biochemical reactions by lowering the activation energy needed to get the reaction going. They are highly specific, only binding to certain substrates (reactants) at their active sites. – If the shape of the active site gets changed, such as due to a change in the pH or temperature of the environment, then the enzyme can no longer function as it should. Enzymes remain unchanged after the reaction and can be reused. They are critical for regulation of life processes in all organ systems that make up an organism!!  Levels of Organization All living things are organized. – An organism is made of organ systems (Ex. the Digestive system) – Each organ system is composed of organs (Ex. Stomach) – Each organ is made of tissues (Ex. Muscle tissue) – Each tissue is made of cells (Ex. Smooth muscle cells) This hierarchy of organization comes about via cell division and differentiation.  Cell Division All cells come from other cells via cell division during the cell cycle. – The cell cycle in somatic (body) cells consists of 3 main phases: Interphase: where the cell spends most of its “life” – DNA is doubled à sister chromatids (I àX) during the end of this phase in preparation for division Mitosis: where the cell begins to divide – Consists of Prophase, Metaphase, Anaphase, and Telophase Cytokinesis: where the cytoplasm splits forming 2 identical daughter cells – These cells are also identical to the parent cell unless a random mutation occurred.  Differentiation Differentiation is the process of stem cells, or undifferentiated cells, undergoing specialization to become specific types of cells with different functions. – Gene expression determines what a cell becomes. The organelles that make up the cell’s structure give insight to the job that the cell specializes in – Form (structure) dictates function!!