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Class Notes2
Biology ch 3 and 21
| Question | Answer |
|---|---|
| The cell theory | A cell is the basic unit of life All living things are made up of cells New cells arise from preexisting cells |
| Steps of chemical evolution | Gases of the primitive atmosphere formed small organic molecules Molecules combined to form macromolecules Only RNA might have been needed to form the first cells and is supported by the fact that RNA can act as enzymes called ribozymes |
| Steps of chemical evolution2 | Protocells made of proteins and lipids could metabolize by using oceanic organic molecules but could not reproduce The true cell can reproduce and has DNA as its genetic material |
| Prokaryotic cells | Thought to be the first cells to evolve Represented by Bacteria and Archaea |
| Eukaryotic cells | More complex Many membrane-bound organelles Represented by Eukarya |
| A plasma membrane | that surrounds and delineates the cell |
| A cytoplasm | that is the semi-fluid portion inside the cell that contains organelles DNA Small size |
| Consider the cell surface-area-to-volume ratio | Small cells have a larger amount of surface area compared to the volume |
| Consider the cell surface-area-to-volume ratio2 | An increase in surface area allows for more nutrients to pass into the cell and wastes to exit the cell more efficiently There is a limit to how large a cell can be and be an efficient and metabolically active cell |
| Compound light microscope | Lower magnification Uses light beams to view images Can view live specimens |
| Transmission electron microscope | 2-D image Uses electrons to view internal structure High magnification, no live specimens |
| Scanning electron microscope | 3-D image Uses electrons to view surface structures High magnification, no live specimens |
| Characteristics of the plasma membrane | It is a phospholipid bilayer It is embedded with proteins that move in space It contains cholesterol for support It contains carbohydrates on proteins and lipids Selectively permeable |
| Passive transport | Diffusion (simple and facilitated) Osmosis |
| Active transport | Active transport Endocytosis phagocytosis Exocytosis |
| Diffusion | is the random movement of molecules from a higher concentration to a lower concentration |
| Osmosis | is the diffusion of water molecules |
| Hypertonic | solutions have more solute than the inside of the cell and lead to lysis (bursting) |
| Hypotonic | solutions have less solute than the inside of the cell and lead to crenation (shriveling) |
| Isotonic | solutions have equal amounts of solute inside and outside the cell and thus does not affect the cell |
| What structures are involved in protein production? | Nucleus Ribosomes Endomembrane system |
| What is the structure and function of the nucleus? | Bound by a porous nuclear envelope Houses DNA and associated proteins called chromatin Contains nucleoplasm Nucleolus region(s) that contain ribosomal RNA (rRNA) |
| What is the structure and function of ribosomes? | Organelles made of RNA and protein Found bound to the endoplasmic reticulum and free floating in the cell Site of protein synthesis |
| What is the endomembrane system? | A series of membranes in which molecules are transported in the cell It consists of the nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes and vesicles |
| Rough endoplasmic reticulum | studded with ribosomes used to make proteins |
| Smooth endoplasmic reticulum | lacks ribosomes but aids in making carbohydrates and lipids |
| Golgi apparatus | flattened stacks that process, package and deliver proteins and lipids from the ER |
| Lysosomes | membranous vesicles made by the Golgi that contain digestive enzymes |
| Vesicles | small membranous sacs used for transport |
| What is the cytoskeleton? | A series of proteins that maintain cell shape as well as anchors and/or moves organelles in the cell Made of 3 fibers: large microtubules, thin actin filaments and medium-sized intermediate filaments |
| What are cilia and flagella? | Both are made of microtubules Both are used in movement Cilia are about 20x shorter than flagella |
| What do mitochondria do and what do they look like? | A highly folded organelle in eukaryotic cells Produces energy in the form of ATP They are thought to be derived from an engulfed prokaryotic cell |
| What is cellular respiration? | Production of ATP in a cell Includes: Glycolysis Citric acid cycle 3. Electron transport chain |
| Enzymes are important for cellular respiration and many activities in the cell | Most enzymes are proteins Enzymes are often named for the molecule that they work on or substrates Enzymes are specific to what substrate they work on Enzymes have active sites where a substrate binds Enzymes are not used up in a reaction but instead |
| Glycolysis – step 1 of cellular respiration | Occurs in the cytoplasm Breaks glucose into 2 pyruvate NADH and 2 ATP molecules are made Does not require oxygen |
| Citric acid cycle – step 2 of cellular respiration | A cyclical pathway that occurs in the mitochondria Produces NADH and 2 ATP Requires oxygen |
| Electron transport chain – step 3 of cellular respiration | Series of molecules embedded in the mitochondrial membrane NADH made in steps 1 and 2 carry electrons here 32-34 ATP are made depending on the cell Requires oxygen as the final electron acceptor in the chain |
| What other molecules besides glucose can be used in cellular respiration? | Other carbohydrates Proteins Lipids |
| How can a cell make ATP without oxygen?Fermentation | Occurs in the cytoplasm Does not require oxygen Involves glycolysis Makes 2 ATP and lactate in human cells Is important in humans for a burst of energy for a short time |
| Fast-twitch fibers | rely on CP and fermentation (anaerobic) Designed for strength Light in color Few mitochondria Little or no myoglobin Fewer blood vessels than slow-twitch |
| Slow-twitch fibers | Rely on aerobic respiration Designed for endurance Dark in color Many mitochondria Myoglobin Many blood vessels |
| DNA is an information-bearing molecule that plays a critical role in | reproduction development everyday functioning of living things |
| DNA structure: A review | Double-stranded helix Composed of repeating nucleotides (made of a pentose sugar, phosphate and a nitrogenous base) Sugar and phosphate make up the backbone while the bases make up the “rungs” of the ladder |
| DNA structure: A review 2 | Bases have complementary pairing with cytosine (C) pairs with guanine (G) and adenine (A) pairs with thymine (T) |
| Ribosomal | joins with proteins to form ribosomes |
| Messenger | carries genetic information from DNA to the ribosomes |
| Transfer | transfers amino acids to a ribosome where they are added to a forming protein |
| Similarities Comparing DNA and RNA | Are nucleic acids Are made of nucleotides Have sugar-phosphate backbones Are found in the nucleus |
| Differences Comparing DNA and RNA | DNA is double stranded while RNA is single stranded DNA has T while RNA has U RNA is also found in the cytoplasm as well as the nucleus while DNA is not |
| Proteins: A review | Composed of subunits of amino acids Sequence of amino acids determines the shape of the protein Synthesized at the ribosomes Important for diverse functions in the body including hormones, enzymes and transport Can denature causing a loss of |
| Transcription | DNA is read to make a RNA in the nucleus of our cells |
| Translation | Reading the mRNA to make a protein in the cytoplasm |
| Transcription | mRNA is made from a DNA template mRNA is processed before leaving the nucleus mRNA moves to the ribosomes to be read Every 3 bases on the mRNA is called a codon and codes for a particular amino acid in translation |
| Modifications of mRNA | One end of the RNA is capped Introns removed Poly-A tail is added |
| The genetic code | Made of 4 bases Bases act as a code for amino acids in translation Every 3 bases on the mRNA is called a codon that codes for a particular amino acid in translation |
| Translation 3 steps | Initiation: mRNA binds to the small ribosomal subunit and causes 2 ribosomal units to associate |
| Translation 3 steps | Elongation: polypeptide lengthens tRNA picks up an amino acid tRNA has an anticodon that is complementary to the codon on the mRNA tRNA anticodon binds to the codon and drops off an amino acid to the growing polypeptide |
| Translation 3 steps | Termination: a stop codon on the mRNA causes the ribosome to fall off the mRNA |
| Regulation of gene expression | not all genes are transcribed in all cells. expression of gene changes over time with the need of the cell. the environment also determines which genes are transcribed. |
| Pretranscriptional control (nucleus): | e.g. chromatin density |
| Transcriptional control (nucleus) | e.g. transcription factors |
| Posttranscriptional control (nucleus) | e.g. mRNA processing |
| Translational control (cytoplasm) | e.g. Differential ability of mRNA to bind ribosomes |
| Posttranslational control (cytoplasm) | e.g. changes to the protein to make it functional |
| The Importance of Regulation | The most important factor in bringing about the differences among organisms is the regulation of the genes. |
| The Importance of Regulation 2 | There does seem to be correlation between the complexity of an organism and the proportion of its DNA that does not code for protein. |
| DNA Protein | Which is worse? mistake in DNA replication. mistake in transcription of RNA. mistake in translation of mRNA |
| Mutations | Types of mutations: Heritable mutations occur germ-line cells Nonheritable mutations occur in somatic cells Mutations are the ultimate source of genetic variation that are essential for evolution. |
| Boy or Girl? | Sex-determining region on the Y chromosome (SRY gene) determines the sex of all mammals |
| Boy or Girl? 2 | males have SRY gene. females do not have SRY gene. SRY gene is only transcribe for a short time in embryonic development. SRY gene is the initial switch to activate male development. protein encoded by SRY gene activates the expression of many. |
| Androgen insensitivity | Sex-determining region of the Y chromosome (SRY gene) |
| What did we learn from the human genome project (HGP)? | Humans consist of about 3 billion bases and 25,000 genes Human genome sequenced in 2003 There are many polymorphisms or small regions of DNA that vary among individuals were identified Genome size is not correlated with the number . |
| Functional genomics | Understanding how the 25,000 genes function Understanding the function of gene deserts (82 regions that make up 3% of the genome lacking identifiable genes) |
| Comparative genomics | Help understand how species have evolved Comparing genomes may help identify base sequences that cause human illness Help in our understanding of gene regulation |
| Proteomics | the study of the structure, function and interactions of cell proteins Can be difficult to study because: protein concentrations differ greatly between cells protein location, concentration interactions differ from minute to minute understanding prote |
| Bioinformatics | the application of computer technologies to study the genome |
| Gene therapy | insertion of genetic material into human cells to treat a disorder |
| Ex vivo therapy | cells are removed from a person, altered, and then returned to the patient |
| In vivo therapy | a gene is directly inserted into an individual through a vector (e.g. viruses) or directly injected to replace mutated genes or to restore normal controls over gene activity |
| DNA technology | Gene cloning through recombinant DNA Polymerase chain reaction (PCR) DNA fingerprinting Biotechnology products from bacteria, plants and animals |
| Recombinant DNA | contains DNA from 2 or more different sources that allows genes to be copies An example using bacteria to clone the human insulin gene: |
| Restriction enzyme | used to cut the vector (plasmid) and the human DNA with the insulin gene |
| DNA ligase | seals together the insulin gene and the plasmid |
| Bacterial cells | uptake plasmid and the gene is copied and product can be made |
| Polymerase chain reaction (PCR) | Used to clone small pieces of DNA Important for amplifying DNA for analysis such as in DNA fingerprinting |
| DNA fingerprinting | Fragments are separated by their charge/size ratios Results in a distinctive pattern for each individual Often used for paternity or to identify an individual at a crime scene or unknown body remains |
| Transgenic bacteria | Insulin Human growth hormone (HGH) Clotting factor VIII Tissue plasminogen activator (t-PA) Hepatitis B vaccine Bioremediation – cleaning up the environment such as oil degrading bacteria |
| Transgenic plant | Produce human proteins in their seeds such as hormones, clotting factors and antibodies Plants resistant to herbicides Plants resistant to insects Plants resistant to frost Corn, soybean and cotton plants are commonly genetically altered |
| Health focus: Ecological concern about BT crops | Resistance increasing in the target pest Exchange of genetic material between the transgenic plant and a related species Concern about the impact of BT crops on non-target species |
| Transgenic animals | Gene is inserted into the egg that when fertilized will develop into a transgenic animal |
| Gene pharming | production of pharmaceuticals in the milk of farm animals |
| Larger animals | includes fish, cows, pigs, rabbits and sheep |
| Mouse models | the use of mice for various gene studies |
| Xenotransplantation | pigs can express human proteins on their organs making it easier to transplant them into humans |
Created by:
lpenn
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