A&P Theory Unit 3 Notes PDF

**[A&P Theory Unit 3 Notes]** **[Unit Student Learning Outcomes]** 1\. Identify the organelles of the cell as well as their function. CSLO 2 -------------------------------------------------------------------------- ------------ 2\. Differentiate the components of the cell membrane a...

**[A&P Theory Unit 3 Notes]** **[Unit Student Learning Outcomes]** 1\. Identify the organelles of the cell as well as their function. CSLO 2 -------------------------------------------------------------------------- ------------ 2\. Differentiate the components of the cell membrane and the mechanisms CSLOs 2, 1 of active and passive transport. 3\. Recognize the structure of DNA and the process of DNA replication. CSLO 2 4\. Recognize the phases of the cell cycle and potential disruptions in CSLOs 2, 4 the cell cycle. 5\. Recognize the process of protein synthesis. CSLO 2 **[Organelles of the Cell:]** Cells are the smallest unit of life. **Robert Hooke:** Proposed cell theory. Cell theory consists of 3 parts: 1. All living things are made of cells 2. The cell performs all the functions necessary for life. 3. All cells come from preexisting cells. Cells contain nucleus and organelles (little organs) **[Nucleus:]** - Human cells are eukaryotic cells- meaning that they have a membrane bound nucleus - Most cells have one nucleus - Control center of the cell - Holds the genetic material (DNA) of the cell. - Surrounded with a nuclear membrane with pores. - Inside the nucleus contains nucleolus where rRNA is made **[Rough Endoplasmic reticulum:]** - Connected to the nuclear membrane - Studded with ribosomes - Synthesis and modification of proteins that are for export **[Smooth Endoplasmic reticulum: ]** - **Lacks ribosomes** - Responsible for making phospholipids for the cell membrane or steroid lipids for hormones - In some cells (muscle) it can store calcium **[Golgi Apparatus: ]** - Receives products from the endoplasmic reticulum - Has two sides: incoming and exiting - Modifies, sorts, and ships the products - Exported products will travel by vesicles to the cell membrane and fuse with it releasing their products **[Lysosome:]** - Come from the Golgi - Contain digestive enzymes for ridding the cell of old organelles or pathogens - Can also be used for apoptosis under some conditions. (Apoptosis is programmed cell death, occurs when a cell is damaged, infected with a virus, or cancerous.) **[Mitochondrion: ]** - Used for energy production - Site of cellular respiration (the process of burning carbohydrates to make energy for the cell.) - Makes 95% of the ATP a cell uses - The inner membrane performs oxidative phosphorylation (making ATP with the electron transport chain.) - They are self- replicating. Mitochondria have their own DNA and their own ribosomes to make needed proteins. - Cells that have a high energy need many thousands of mitochondria **[Peroxisome: ]** Perform many functions in the cells Lipid metabolism Chemical detoxification Enzymes in peroxisomes are used for making H2O2 (Hydrogen peroxide) and then reducing it to water. This reduces oxidative stress on the cell from free radicals. **[Oxidative Stress: ]** - Reactive Oxygen Species (ROS) are very reactive molecules contain oxygen and are unstable. - They try to donate extra electrons to other molecules - Free radicals- steal or donate electrons, causes cell damage - The extra electrons damage cells and are responsible for the aging process, atherosclerosis, neuronal diseases, mutation, cancer. **[Examples of ROS include: ]** - The hydroxyl radial (OH) - Hydrogen Peroxide (h2o2) - Superoxide **[Where do they come from? ]** - Through oxidative phosphorylation in the mitochondria - Inflammatory pathways - Respiratory burst by neutrophils - Ischemia (lack of blood flow). **[External factors can create highly reactive ROS in our cell: ]** - Smoking - Drugs and alcohol - Pollution - Chemicals like pesticides - UV radiation - Peroxisomes can help neutralize the ROS - Antioxidants that come from fruits and vegetables and vitamins A, C, and E can help rid the body of these reactive molecules. **[Cytoskeleton: ]** - **[Functions: ]** - Cell support - Cell movement - Cell division - Transportation inside the cells The cytoskeleton is a group of fibrous proteins that provide structural support for cells, are critical for cell motility, cell reproduction, and transportation of substances within the cell. - **[Three fibrous proteins: ]** - [**Microtubules**:] support and maintain organelle position - [**Intermediate filaments**:] cell shape and support - **[Microfilaments]**: movement **Microvilli:** - Made of microfilaments of the cytoskeleton - Increase absorptive area of a cell **Flagellum:** - Made of microtubules of the cytoskeleton - Only human cell that uses flagella are sperm - Used to propel sperm - Longer than Cilla **Cilia:** - Made of microtubules of the cytoskeleton - Have the motility to move substance across cell surfaces - Longer than microvilli **Centriole:** - Centrioles make microtubules - The microtubules help separate chromosomes during mitosis **[Ribosomes:]** Makes proteins **[Microvilli:]** Increases surface area/absorptive area of the cell **[Lysosomes:]** digestive sacs **[Golgi apparatus]**: modifies, sorts, and packages material for export **[Smooth ER:]** makes cell membrane lipids **[Cilia:]** moves particles across the cell surface **[Cytosol:]** liquid-like portion of the cytoplasm absent the organelles **[Flagellum:]** allows sperm to swim **[Rough ER:]** makes protein within a membrane for export **[Nucleus:]** holds the genome of the cell **[Mitochondrion:]** site of energy production **[Cytoskeleton:]** helps maintain cell shape **[Centrioles:]** guides DNA during mitosis **[Microtubules:]** large fibrous proteins of the cytoskeleton **[Peroxisomes:]** important in cell detoxification of free radicals **[The Cell Membrane and Active and Passive Transport ]** **[Cell membrane functions:]** acts as a barrier, being used as a self-identifier, and contains receptors for hormones. **[Semipermeable]**: Allows some molecules to pass through and inhibits others **[Hydrophobic:]** Non-polar, fearing water **[Hydrophilic:]** Polar, likes water **[Amphipathic: Contains both a hydrophobic and hydrophilic part, ie. phospholipid]** **[Solute:]** The molecules that dissolve in the solvent **[Solvent:]** The substance that can dissolve molecules (usually water) **[Ligand:]** A molecule that binds to a protein on the cell membrane **[Concentration gradient:]** Difference in concentration of substances across the membrane **[Glycocalyx: ]** - Made up of glycoproteins, glycolipids, and other sugars - Helps protect and lubricate cells - Helps with binding to other cells - Can have receptors or enzymes - Big role is self-identify **[Phospholipid bilayer:]** - Phospholipids move laterally - Selectively permeable - Consists of hydrophobic tails (interior) and hydrophilic heads (exterior) - Hydrophilic (phosphate) head: polar, consists of phosphate and glycerol - Hydrophobic (fatty acid) tail: are non-polar unsaturated and saturated fatty acids, have kinks. **[Peripheral protein:]** Attached to one side of membrane - Only on one side of the membrane - Can aid in cell signaling or act as enzymes **[Glycolipid: ]** - Contain carbohydrates for cell identity and act as identifiers and part of the glycocalyx (lipid + carbohydrate) **[Cholesterol:]** Stabilize the plasma membrane - A ringed lipid made by the body that helps stabilize the plasma membrane and maintain fluidity **[Integral Protein:]** Built into the membrane/ channel proteins - Pass all the way through the membrane - Channel proteins - Can act as receptors to bind ligands. **[Passive Transport:]** uses the concentration gradient of a substance, s**o no energy or ATP is required.** Include **diffusion, facilitated diffusion, and osmosis.** Particles move through the cell membrane to areas of high concentration to lower concentration without the use of energy. **Types of passive transport:** **[Diffusion:]** When particles move from an area of high concentration to low concentration. Does not require energy. - Can happen with or without a semipermeable membrane. - A natural process - Greater differences in the concentration of substances will make molecules move more quickly ex- oxygen and carbon dioxide, lipids. - **Solutes** move from high concentration to low concentration **[Osmosis:]** is diffusion that happens with water molecules. Movement of water from areas of high water concentration to low water concentration. - Diffusion of water through the cell membrane. - Water molecules can enter or leave the cell membrane until it reaches equilibrium. - No energy is required - The water moves from high water concentration to low water concentration. - Where there is a high solute concentration, there is a low water concentration Low **Solute**/High **water**, High **Solute**/Low **water** concentration. **Isotonic Solution:** Solution is equally concentrated to the cell cytosol. ex- normal saline **Hypertonic solutions**: Solution is more concentrated than cell cytosol. Water flows out of the cell, resulting in cells shrinking or crenation. Ex-salt water **Hypotonic solutions:** Solution is less concentrated than the cell cytosol, water flows into the cell, resulting in swelling or even bursting. Hemolysis in red blood cells. Ex- pure water **[Facilitated Diffusion:]** Molecules diffuse through specialized protein channels in the cell membrane - Protein Channels act as ports that allow substances in or out of the cell. - High concentration to low concentration. - Happens with particles that are larger, along the concentration gradient through protein channels. Ex- glucose, ions, polar molecules **[Types of Protein Channels: ]** **Ion Channels:** - Allows different ions to pass **Channel Protein:** - Less discriminating - Movement is based on size or charge **Carrier protein:** - Only allow one type of molecule - Some can move two different molecules in same direction **[Active Transport:]** Particles move from areas of low concentration to high concentration. - Moves substance against the concentration gradient or must expend energy to perform the transport, so it **will need energy or ATP.** - Requires energy **[Types of Active Transport: ]** **[Endocytosis:]** (enter the cell) - Phagocytosis- larger molecules or pathogens - Receptor-mediated endocytosis uses receptors for specific molecules (ligands). - Pinocytosis- small molecules and liquids. **[Exocytosis:]** (Exit the cell) - Something needs to exit the cell Protein Pumps: moves ions in or out of the cell Ex- Sodium/Potassium Pump, Moves sodium out of the cell and potassium into the cell. **[DNA and DNA Replication: ]** **[Gene:]** Sequence of DNA that codes for a single protein **[Chromatin:]** Loose strand of DNA **[Chromosome:]** Condensed structure of DNA and proteins formed during cell division; in humans arranged in 23 pairs **[Bases: ]** - DNA is a nucleic acid made of nucleotides containing nitrogenous bases. The bases are arranged in complimentary base pairs. - Two stands of DNA form a double-helix. **[Nitrogenous Bases: ]** Adenine (A)\ Thymine (T) Cytosine (C) Guanine (G) - DNA also contains the sugar deoxyribose and phosphate groups. - Complimentary bases are A-T and C-G - Bases are held together by hydrogen bonds **[Chromatin:]** - DNA is usually found in loose strands called chromatin. - Chromatin is wound around proteins (histones) for packaging and called a nucleosome. ### **[Chromosome: ]** - During cell division, the chromatin will condense and become visible. This is known as a chromosome. - Humans have 23 pairs of chromosomes, to a total of 46 chromosomes. **[Genes: ]** - Both forms of DNA, loose chromatin and densely coiled chromosomes, still hold the genes each cell needs to operate. - A gene is a segment of DNA that codes for a product, usually a protein. - The sequence of bases found on DNA is the genetic code that is read to make a protein. - Before a cell can divide, the DNA in the cell needs to replicate so each new cell gets all the DNA needed to function properly. **[Helicase:]** An enzyme needed for replication; helicase separates the hydrogen bonds between the base pairs. [**DNA Polymerase:** ] - An enzyme needed for replication. DNA polymerase brings in the complimentary base to build a new strand. - Once two new stands are built the process stops [**DNA Replication:**] DNA duplicates itself - During S phase in cell cycle. S stands for Synthesis- make - Necessary to produce identical daughter cells during mitotic cell division. - Unwound DNA strands serve as templates for new complementary strands. - DNA polymerase and other enzymes add nucleotides to template strands following base pair rule. 1^st^ step: Unwinding of DNA strand by helicase enzyme. Breaks hydrogen bond between nitrogenous bases. 2^nd^ Step: Creation of two new identical strands by DNA polymerase. Two duplicate DNA produced. **[Phases of the Cell Cycle and Potential Disruptions: ]** **Diploid:** A cell with two copies of a chromosome **Homologous:** A pair of chromosomes, one from each parent **Sister Chromatid:** Exact copies of DNA molecules found during mitosis **Centromere**: Attaches two sister chromatids together **Somatic Cell:** Normal body cells (Does not include sex cells: eggs or sperm) **Sex Cell:** Cells containing one half (haploid) of the somatic cells - Before cells can divide, their DNA must be copied. The resulting DNA is arranged in sister chromatids, and in homologous pairs. - **Cell Cycle: lifespan of a eukaryotic somatic (any cell besides sex cells) cell. Happens in 4 Phases.** **[Interphase:]** Consists of G0, G1, S, G2 Phases. Interphase is the time when a cell is not dividing. Interphase is where the cell will do normal cell functions and prepare for division. G0: Resting phase of the cell cycle G1: First Growth phase, cell is growing, doing normal functions S: Cell enters S (Synthesis) phase when it grows and no longer able to function well, and needs to divide. A copy of DNA is being made. (DNA replication) G2: Growth 2/Gap Phase 2. More cell division preparation. (Mitosis) **[M Phase:]** Cell Division consists of Mitosis and Cytokinesis **[Mitosis]**: Division of the cell\'s nucleus. Further divided into 4 phases. - **Prophase:** Longest phase. Chromatin begins to condense into the shape of chromosomes. The nucleolus and nuclear membrane disappears. **Chromosomes begin to appear. Spindle fibers begin to form.** Sister chromatids are held together by centromeres in the middle that make up the chromosome. - **Metaphase:** Centrioles complete movement, and the **chromosomes line up to the middle** (equator of the cell). Spindle fibers align the chromosomes in the middle. - **Anaphase:** **spindle fibers separate sister chromatids at their centromere into two separate groups of chromosomes. Pull towards poles.** They are now individual chromosomes, the spindle fibers shorten, and they are a V shape. Move to opposite sides of the pole towards centrioles. Centrioles are at the poles. - **Telophase:** Nuclear membrane and Nucleolus reforms around chromosomes, then chromosomes spread out into chromatin. **[Cytokinesis:]** Division of the cytoplasm. In animal cells cytokinesis occurs through the inward movement of the cell membrane, progressively pinches until **2 identical daughter cells are formed.** - At the end of M phase, you have two daughter cells identical to each other, and to the original cell. **[Checkpoints: ]** - During the normal cell cycle there are three checkpoints where the cell either proceeds or stops. **[G1 Checkpoint:]** The G1 checkpoint is when the cell needs to be ready to replicate the DNA. The cell is large enough has enough reserves for DNA replication. **[G2 Checkpoint:]** The G2 checkpoint is when the cell needs to be ready for mitosis. The DNA must be properly replicated. **[M Checkpoint:]** The M checkpoint occurs during metaphase of mitosis to make sure all sister chromatids are attached and in the proper places so each cell gets a complete set of chromosomes. **[Potential Disruptions to the Cell Cycle: ]** **[Cyclins:]** Cyclins are a common cell signal regulating mitosis. **[Proto-oncogenes:]** Proto-oncogenes tell the cell to divide. **[Tumor suppressor genes:]** Tumor suppressor genes tell the cell to stop. **[Mutations:]** A change in the nucleotide sequence in a gene within a cell's DNA, potentially altering the protein coded for that gene. **[Reactive Oxygen Species (ROS)]** can cause permanent damage to: ex- hydrogen peroxide - cellular lipids - proteins - carbohydrates - nucleic acids - Damaged DNA can lead to genetic mutations and cancer - Lack of cell regulation can allow cells to grow out of control - Cancerous cells lack contact inhibition, don't resemble the cell of origin and often invade nearby tissues. Potential causes for cancer: - An abnormal oncogene with a continuous go signal - A lack of tumor suppressor genes that don\'t tell the cells to stop - Cancerous cells that travel to new sites are metastasizing. **[Protein Synthesis: ]** **[Base Pairing:]** Two bases bonded together making the rung of the DNA and used to create DNA or RNA. (A-T, C-G in DNA; A-U, C-G in RNA) **[Transcription:]** DNA to RNA **[Translation:]** RNA to protein **[Sense codons:]** Codes for an amino acid **[Stop codons:]** Stop signs for translation **[Anticodons:]** Found on tRNA; complementary bases to the mRNA codon **[Polypeptide:]** Small proteins made with amino acids joined by peptide bonds. **Codon:** part of a gene containing the code for each specific amino acid in a protein (3 nitrogenous bases) **Triplet:** - The process of protein synthesis occurs is a series of steps starting in the nucleus and ending at the ribosome. - Proteins are shape dependent and run many of the cells function as enzymes. - The process of making protein is gene expression, not all genes are expressed at all times. - DNA \> RNA \> Protein - Triplet \> Codon \> Amino Acid - Most types of RNA, including mRNA, are single-stranded and contain no complementary strand. - RNA is important for building proteins - RNA contains ribose, whereas DNA has deoxyribose. - Instead of the base thymine, RNA contains the base uracil. This means that adenine will always pair up with uracil during the protein synthesis process. **[Transcription:]** Process of building messenger RNA. It takes place in the nucleus. (Has nothing to do with replication) **[Process of copying genetic 'code' into mRNA]** - First step in process of using genetic code in DNA to synthesize different proteins - Place proteins are made are outside nucleus (In ribosomes) - DNA uses MRNA (messenger RNA) to carry genetic code from the nucleus to the ribosome - Transcription beings when enzyme RNA polymerase attaches to a gene. - Gene contains code to build protein - RNA polymerase causes a specific area of a DNA strand to unwind and separate into two strands - Template strand- transcribed by RNA, contains complementary bases - Non-template strand- not transcribed - DNA is written in three base groups called a triplet. - RNA is written in three bases called codons. - MRNA is a copy of the non-template strand with Uracil instead of thymine **[Translation:]** Building the protein at the ribosome - Translation uses the mRNA and the ribosome to create a protein - The process of translation begins at a start codon (AUG) and ends when it reaches a stop codon. 1. mRNA leaves the nucleus through a pore and associates with a ribosome (made of rRNA) either in the cytoplasm or attached to the endoplasmic reticulum. 2. The ribosome "reads" the mRNA and tRNA carries in the complimentary anticodon that matches the codon on mRNA. If the codon is AUG then the anticodon is UAC. 3. Each tRNA drops off the amino acid it carries, and the amino acids are joined together by peptide bonding. The polypeptide made is the primary sequence of that protein. 4. The polypeptide leaves the ribosome and will either be ready for use or undergo more processing by the RER and Golgi.