Biology Chapter 7
***Light reaction cannot occur unless light is present
(light dependent reaction)
*When NADP+ carries hydrogen atoms, it becomes NADPH
**ATP is also carried from light reactions to the calvin cycle reactions
Describe the roles of RNA molecules in the gene expression
*Gene Expression - process of using the information within a gene to synthesize a protein. - mRNA : carries transcribed genetic code - tRNA: brings the amino acids to the ribosomes so that the ribosome can make protein - rRNA: makes up the ribosomes that build the amino acid chain
Summarize the causes of gene mutations
*Gene Mutations: permanent change in the sequence of bases in the DNA I. Errors in DNA mutation - rare source of mutations - DNA polymerase : enzyme that carries out replication : proofreads the new strand against the old strand - usually mismatched pairs are then replaced with the correct nucleotides II. Mutagens - environmental influences causes mutations in humans - include radiation and organic chemicals : UV radiation, X-ray, chemicals in cigarette smoke - rate of mutations resulting from mutagens is generally low III. Transposes - specific DNA sequences that have the remarkable ability to move within and between chromosomes - also known as jumping genes: found in bacteria, fruit flies and humans
What are the outputs of glycolysis?
- 2 (3C) pyruvate - 2 NADH - 2 ADP - 4 ATP
Describe Fixation of carbon dioxide
- 3 molecules of CO2 are attached to three molecules of RuBP, a 5-carbon molecules - Result = three 6 - carbon molecules - Each 6 - molecule then splits into half = six 3 - carbon molecules - First 3 - carbon molecule is 3 - phosphoglycerate (3PG) - Enzyme that speeds the reaction is called RuBP carboxylase (RuBP Carboxylase) - a protein that makes about 20% - 50% of the protein content in chloroplast
What are the inputs of glycolysis?
- 6C glucose - 2 NAD+ - 2 ATP - 2 ADP + 2P
Describe the electron Transport Chain
- Utilizes oxygen as final receptor of electrons - Aerobic - series of membrane-bound carriers that pass electrons from one carrier to another - High energy delivered, Low energy leave - Like stairs when something bounces down it loses potential energy, electrons pass through from high to low and energy is released and used for ATP synthesis - Electrons contribute to the production of the majority of the ATP
Determine the sequence of amino acids in a polypeptide, given messenger RNA sequence
- When mRNA is formed it has a sequence of bases complementary to that of the DNA; wherever A,T,G and C are present in DNA ; U,A,C and G are incorporated into the mRNA molecule respectively. - Every three mRNA bases is a codon (a triplet code) for a certain amino acid
DNA polynucleotide strand
- backbone made up of alternating phosphate and sugar molecules - two strands twist about one another in the form of a double helix (anti-parallel) - strands are held together by hydrogen bonding : A & T - form 2 hydrogen bonds : G & C - form 3 hydrogen bonds *aka complimentary base pairing
Describe why cancer is a failure of genetic control
- cancer is a disease characterized by unrestricted cell growth - as a cancer cell continues its unregulated division, it may form a population of cells: tumor * Benign : surrounded by a fibrous capsule (usually made of connective tissue) : mole is an example of a benign tumor (aka melanocytes) * Malignant : do not assemble normal cells, are able to invade surrounding tissues : they may come in contact with either blood or lymph vessels : associated with lung cancer (mostly dangerous)
Anaphase
- centromeres uniting the sister chromatids divide - sister chromatids divide then separate, becoming daughter chromosomes that move toward the the opposite poles of the spindle - daughter chromosomes have a centromere and a single chromatid
Prophase
- centrosomes begin moving away towards opposite ends of the nucleus - Spindle fibers appear and nuclear envelope begins to fragment - Chromatin condenses and chromosomes are now visible.
Explain the role of photosynthesis for all organisms on Earth
- converts solar energy into the chemical energy of a carbohydrate
Termination
- final step in protein synthesis - polypeptide and the assembled components that carried out protein synthesis are separated from one another - occurs at the stop codon - requires a protein called a release factor which cleaves the polypeptide from the last tRNA - the polypeptide is set free and begins to take on its three-dimensional shape - the ribosomes dissociates into its two subunit
Metaphase
- fully formed spindle consists of poles, asters and fibers - metaphase plate: plane perpendicular to the axis of the spindle and equidistant from the poles. - chromosomes attached to centromeric spindle fibers are lined up at the metaphase plate
Metaphase I
- homologous chromosome pairs align at the metaphase plate - independent assortment: depending on how they align, the maternal or paternal member of each pair may be oriented toward either pole
Anaphase I
- homologous chromosomes pair separates - each chromosomes, consisting of two identical sister chromatids, moves toward opposite poles of the cell - generating cells with different combinations of maternal and paternal chromosomes
Describe the molecules necessary for translation
- mRNA : codes for a particular sequence of amino acid to form polypeptide - tRNA: bring molecules to ribosomes for protein synthesizes - rRNA: produced in nucleolus // joins with proteins to form 2 ribosomal subunits - ribosomes: site of translation (found in cytoplasm and rough ER)
Interkinesis
- period of time between meiosis I and meiosis II - no replication of DNA during this phase as chromosomes are already duplicated
What is chlorophyll?
- pigment that gives them a green color - Green chlorophyll can be masked off by other pigments
What are Autotrophs?
- plants, algae, cyanobacteria - produce their own food - also known as photosynthetic organisms
Describe photosynthesis in terms of two sets of reactions in the chloroplast
2 sets of reactions: light reactions and the Calvin Cycle Reaction (light-independent reaction)
Summary of the Preparatory Reaction, Citric Acid Cycle, and Electron Transport Chain STEP 2
Acetyl group enters the citric acid cycle (series of reaction located in mitochondrial matrix). Complete oxidation follows, as two CO2, three NADH + H+ and one FADH2 are formed. The cycle produces one ATP. Entire cycle must turn twice per glucose molecule.
Summary of the Preparatory Reaction, Citric Acid Cycle, and Electron Transport Chain STEP 3
Final stage, electron transport chain located in cristae of mitochondria. The electrons received from NADH and FADH2 are passed down a chain of electron until they are received by O2, which combines with H+ to produce H2O. As electrons pass down the chain, ATP is produced
What is the equation of cellular respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O -ADP + P is added into the reaction and turns into ATP (36-38)
Name the pigments required to absorb light energy for photosynthesis
Chlorophyll, (carotenoids), and (phycobillins)
Describe the important events of meiosis that cause the halving of the chromosome number in daughter cells.
During meiosis II, the centromeres divide and the sister chromatids separate, becoming daughter chromosomes that are distributed to daughter nuclei
What happens if the oxygen is not available?
Fermentation occurs in the cytoplasm instead of continued aerobic
Describe the important events of meiosis that cause the genetic diversity of gamete cells.
Fertilization restores the diploid number of chromosomes in a cell that will develop into a new individual
G1 phase
The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. *The cell is not dividing during this stage
Describe the human life cycle in terms of haploid and diploid cells.
The human life cycle requires both meiosis and mitosis. A haploid sperm (n) and a haploid egg (n) join at fertilization, and the resulting zygote has the full, diploid (2n), number of chromosomes. When a haploid sperm fertilizes a haploid egg, the zygote is diploid. The zygote undergoes mitosis as it develops into a newborn child. Mitosis continues throughout life during growth and repair
M phase
The phase of the cell cycle that includes mitosis and cytokinesis. *This is where division occurs *It takes up only 10% of the cell cycle
G2 phase
The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs. * Occurs after DNA replication has taken place * By the end of G2, the cell would have completed its preparations for Division *The cell is not dividing during this stage
S phase
The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. *DNA Chromosomes are replicated during this stage * Each chromosomes are replicated during this itself *This leads to the formation of two (2) sister chromatins *Replicated forms of a chromosome that are genetically centralized joined together by a centromere *centralized region joining two sister chromatids
Describe the checkpoints of the cell cycle
G1 checkpoint--> cell cycle main checkpoint. If DNA is damaged, apoptosis will occur. Otherwise, the cell is committed to divide when growth signals are present and nutrients are available. G2 checkpoint-->Mitosis checkpoint. Mitosis will occur if DNA is damaged and cannot be repaired. M-checkpoint-->Spindle assembly checkpoint. Mitosis will not continue if chromosomes are not properly aligned. *Catastrophic genetic damage can occur if cells progress to the next phase of the cell cycle before the previous phase is properly completed
Phycobillins
Give red algae their red color and cynabacteria a bluish color - capable of absorbing solar energy
Explain what is meant by the term homologous chromosomes.
In humans, we have 46 chromosomes = 23 pairs - there are two pairs of chromosomes - the members of a pair are called homologous chromosomes - homologous chromosomes will be the same size but different color : blue chromosomes inherited from one parent : red from the other
What is a disadvantage of fermentation?
It produces ATP for only 20-30 seconds because the lactic acid is toxic to the cell
What is an advantage of fermentation?
It releases energy without the presence of oxygen
Describe Fermentation
Lactic Acid Fermentation: - pyruvate formed is reduced to form lactate -> converted to lactic acid in the water environment of the cell - Electrons needed to reduce pyruvate are supplied by NADH molecules from glycolysis - Absence of O2, the NAD+ is regenerated when pyruvate is reduced - Lactic acid helps to recycle NAD+ molecules and allows glycolysis to proceed with ATP production
Meiosis II
Prophase II : a spindle appears while the nuclear envelope disassembles and the nucleolus disappears Metaphase II : chromosomes align on metaphase plate Anaphase II : sister chromatids separate Telophase II : Spindle disappears, nuclei form and cytokinesis takes place * Daughter cells: results in 4 haploid daughter cells
Differentiate between proto-oncogenes and tumor suppressor genes in their regulation of the cell cycle.
Proto-oncogenes : respond to stimuli; makes cycle progress. : Genes that turn ON or INCREASE the rate of cell division. When these genes are active CELLS GROW and DIVIDE. When normal cells stop dividing, the genes turn off. Tumor-suppressor genes : inhibit the cell cycle; mutated suppressor genes can lead to cancer : Genes that turn OFF or DECREASE the rate of cell division. Genes that repair DNA mistakes. Genes that play a role in apoptosis.
Summary of the Preparatory Reaction, Citric Acid Cycle, and Electron Transport Chain STEP 1
Pyruvate enters the inside of the mitochondria (prep reaction takes place) oxidation occurs as CO2 is removed. NAD+ and FAD are reduced and CoA receives the C2 acetyl group that remains. *Reaction takes place twice per glucose, 2 NADH + H+ results
Glucose phosphate
can be combined with fructose (phosphate removed) to form sucrose. - starting point for the synthesis of starch and cellulose. - use hydrocarbon skeleton of G3P to form fatty acids and glycerol: which are combined in plant oils, such as corn oil, sunflower oil and olive oil (when nitrogen is added to the hydrocarbon skeleton derived from G3P, amino acids are formed, allowing the plant to produce protein // oils are being used as a new source of fuel: bio diesel)
Avery (1944)
continuation of Griffith: what caused the transfer of genetic material? - proteins or nucleic acids which caused this? Isolated proteins, carbohydrates and nucleic acid from live S bacterial and exposed it to R bacteria. -only the R bacteria exposed to nucleic acid became disease-causing + this means that the nucleic acid is the one that has the genetic material RESULT: identified nucleic acid as the genetic material (however it was boot excepted)
Thylakoids
flattened sacs formed by the stroma
What is the stroma?
fluid-filled interior of a chloroplast
Describe the three phases of the calvin cycle
i. Fixation of carbon dioxide ii. Reduction of carbon dioxide iii. Regeneration of RuBP
Summarize the phases of cellular respiration and indicate where each occurs in the cell
i. Glycolysis (outside the mitochondria) ii. Preparatory Reaction (inside the mitochondria) iii. Citric Acid Cycle (inside the mitochondria) iv. Electron Transport Chain (inside the mitochondria)
Granum
stacked thylakoids (grana is plural for granum)
What happens during fermentation?
pyruvate is reduced to lactate to CO2 and alcohol
Hershey and Chase (1952)
radioactive labeling of bacteriophages - labeled proteins w/ radioactive phosphorus - labeled DNA w/ radioactive sulferlet the radioactive bacteriophages attack bacteria - only found traces of radioactive sulfur inside infected bacteria cells + Bacteriophage: virus that attacks bacteria RESULT: definitive evidence that DNA is genetic material
What is the Calvin Cycle?
reduces CO2 to a carbohydrate (coenzyme NADP+ carries hydrogen atoms form light reaction to calvin cycle reaction)
Summarize the events that occur during the process of DNA replication
- After DNA double helix unwinds, each parental strand serves as a template for the formation of new daughter strands. - Two helices, each with daughter and parental strand (semiconservative) are produced during replication : The enzyme (DNA Helicase) unwinds and 'unzips' the double stranded DNA by breaking the weak hydrogen bonds between the paired bases : New complementary DNA nucleotides fit into place by the process of complementary base pairing. : Positioned and joined by DNA Polymerase (uses each original strand as a template for the formation of a complementary new strand) : Because strands of DNA are oriented in an antiparallel configuration, the DNA polymerase may add a new nucleotide only to the end of the chain. (DNA synthesis occurs in the opposite direction) = LEADING STRAND: follows helicase enzymen = LANDING STRAND: formation of short segments of DNA (okazaki fragments) : To complete replication, the enzyme DNA ligase connects the okazaki fragments and seals any breaks in the sugar-phosphate backbone : The two double-helix molecules are identical to each other and to the original DNA molecule
Describe the reasons for and process of apoptosis
- Apoptosis = programmed cell death - It removes unwanted tissues and abnormal cells - Process : during apoptosis, cells round up and loses contact with its neighbors : nucleus membrane and plasma membrane develops blisters : finally, they are engulfed by white blood cells.
Explain how mitosis maintains the chromosome number from the mother cell to the daughter cells.
- Before nuclear division occurs, DNA replication occurs, duplicating the chromosomes. - Each replicated chromosomes is composed of two sister chromatids held together in a region called the centromere. - Sister chromatids are genetically identical = same DNA sequences. - Thus, at the completion of mitosis, daughter nucleus has the same number of chromosomes as their parental cell.
Describe the similarities and differences between cellular respiration and photosynthesis
- Both photosynthesis and cellular respiration utilize and electron transport chain and ATP synthesize. - Photosynthesis reduces CO2 to a carbohydrate // oxidation of H2O releases O2 - Respiration oxidizes carbohydrate and CO2 is given off // O2 is reduced to H2O
Describe the characteristics of cancer cells
- Cancer cells are genetically unstable : linked to mutagenesis : acquires mutation and continues to divide : most aggressive cell becomes the dominant cell of tumor - Cancer cells do not correctly regulate the cell cycle : cancer cells continue to cycle through the cell cycle : rate of cell division and number of cells increase (normal cells cant stop cycle) - Cancer cells escape the signals of death : genetic damage cell with the cell cycle will initiate apoptosis : cancer cells do not respond to programmed cell death and continues to divide :Telomeres occurs (normal cells stop entering cell cycle) : cancer cells turn on the gene that encodes the telomerase enzyme - capable of rebuilding and lengthening the telomerase - Cancer cells can survive and proliferate elsewhere in the body : cancer cells disrupt normal adhesive mechanism and move to another place within the body : Metastasis - travel through blood and lymphatic vessels (invading new tissues) : Angiogenesis - tumor switch genes that code for the production of growth factors encouraging blood vessels formation (supplying tumor cells with nutrients and oxygen for rapid growth)
What are heterotrophs?
- Consumers feeding off autotrophs - must take in preformed organic molecules
Describe the structure of DNA
- DNA is made up of molecules called nucleotides. - Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. - The four types of nitrogen bases are Adenine (A), Thymine (T), Guanine (G) and Cytosine (C) *Purines: A and G - with double ring *Pyrimidines: T and C - with single ring
Compare and contrast the processes of meiosis and mitosis
- DNA replication takes place only once prior to either meiosis or mitosis. However, meiosis requires two nuclear divisions, whereas mitosis requires only one nuclear division - meiosis followed by cytokinesis produces four daughter cells. mitosis results in two daughter cells - the four daughter cells following meiosis are haploid and have half the chromosome number as the parental cell. The daughter cells following mitosis have the same chromosome number as the parental cell - the daughter cells resulting from meiosis are not genetically identical to each other or to the parental cell. whereas in mitosis, the daughter cells are genetically identical to each other and the parental cell
Cytokinesis
- Division of the cytoplasm begins in anaphase and continues in telophase but does not reach completion until just before the next interphase. - The newly forming cells have received a share of the cytoplasmic organelles that duplicated during the previous interphase.
Describe Glycolysis
- Does not utilize oxygen - Anaerobic - Breaks down glucose (C6H12O6) into two molecules of pyruvate, a C3 molecule - Oxidation by removal of electrons (e-) and hydrogen ions (H+) provides enough energy for the immediate buildup of two ATP
Explain the role of mitosis in the cell cycle.
- Mitosis is nuclear division in which the chromosomes number stays constant. : A 2n nucleus divides to produce daughter nuclei that is also 2n. - Mitosis occurs when tissues grow or repair. - Mitosis continues during development and the life span of an individual (eg: zygote) - The purpose of mitosis is cell growth, regeneration, and asexual reproduction
Describe Reduction of carbon dioxide
- Each of two 3PG molecules undergoes reduction to G3P in 2 steps - First Step: converts 3PG into 1, 3 - bisphosphoglycerate (BPG) using ATP - Second = converts BPG into glyceraldehyde - 3 - phosphate (G3P) using NADPH
Describe the stages of the cell cycle and what happens in each stage.
- G1 phase - S phase - G2 phase - M phase
Describe the investment phase of glycolysis
- Glycolysis begins, 2 ATP are used to activate glucose - The molecule that results splits into two 3 - carbon (C3) molecules, aka G3P - Each of which is attached to a phosphate group - This point on, each C3 molecule undergoes the same series of reactions
Identify the electron donor and electron acceptors in the light reactions
- H2O provides electrons for light reactions - NADP+ is the final electron acceptor
Compare the overall chemical equations for both photosynthesis and cellular respiration
- In Photosynthesis, hydrogen atoms are donated by NADPH + H+, when CO2 is reduced in the stroma of the chloroplast. - In Photosynthesis, carbon dioxide and water is yielded to glucose and oxygen. - In respiration, NADH forms when glucose is oxidized in the cytoplasm and glucose breakdown products that are oxidized in the matrix of a mitochondrion. - In respiration, glucose and oxygen is yielded to carbon dioxide and water.
Prometaphase
- Kinetochores (spindle fiber) appear on each side of the centromere - fibers attach the sister chromatids to opposite poles of the spindle - chromosomes are being pulled to opposite poles form alignment
Outline the major events that occur during meiosis I and II, focusing on the activities of chromosomes.
- Meiosis I : Prophase I : Metaphase I : Anaphase I : Telophase 1 : Interkinesis - Meiosis II : Prophase II : Metaphase II : Anaphase II : Telophase II
Describe the purpose of meiosis.
- Meiosis reduces the chromosomes number in such a way that the daughter nuclei receive only one of each kind of chromosome - reduces the chromosome number from diploid (2n) to haploid (n) - as a result of sexual reproduction, the next generation of individuals will have the diploid number of chromosomes and combination of traits different from that of either parent.
Describe the Harvesting phase of glycolysis
- Oxidation of G3P occurs by removal of hydrogen atoms (H+ and e-) - Hydrogen atoms are picked up by NAD+ and NADH + H+ results - NADH passes electron on to the electron transport chain - Results in four high-energy phosphate groups used to synthesize four ATP - Substrate-level ATP synthesis: enzyme passes a high-energy phosphate to ADP ----subtracting the two ATP that were used to start the glycolysis process, it yields a net gain of 2 ATP
List and summarize the events of the phases of mitosis and cytokinesis.
- Prophase - Prometaphase - Metaphase - Anaphase - Telophase - Cytokinesis
Explain the process of gamete production in male and female humans.
- Spermatogenesis - Oogenesis
What are the characteristics of an anaerobic phase of cellular respiration?
- Takes place outside the mitochondrion - Does not utilize oxygen - Glycolysis
Describe Regeneration of RuBP
- Takes three turns of the calvin cycle to allow one G3P to exit - For each turn, five molecules of G3P are used to re-form three molecules of RuBP
Describe the Preparatory Reaction
- Utilizes oxygen as final acceptor of electrons - Aerobic - pyruvate is oxidized to a C2 acetyl group carried by CoA (coenzyme A) and CO2 is removed - Reaction occurs twice per glucose molecule, since glycolysis ended w/ two pyruvate molecules
Elongation
- protein synthesis step in which a polypeptide increases in length one amino acid at a time - elongation factors which facilitate the binding of tRNA anticodons to mRNA codons at a ribosome - 4 steps:- : a tRNA with an attached peptide is at P site and a tRNA carrying the next amino acid in the chain is just arriving at the A site : once the next tRNA is in place (A site), the peptide chain will be transferred to this tRNA : energy and part of the ribosomal subunit are needed to bring about this transfer. (energy contributes to peptide bond formation, which makes peptide amino acid longer at A site) : translocation occurs, the mRNA moves forward one codon length and the peptide-bearing tRNA is now at the ribosome P site. The "spent" tRNA now exits.
Telophase
- spindle fiber disappears and the nuclear envelope components reassemble around the daughter chromosomes - each daughter nucleus contains the same number and kinds of chromosomes as the original parental cell
Starch
- storage form of glucose - some starch stored chloroplast - most starch stored in amyloplasts in roots
Prophase i
- synapsis occurs - homologous chromosomes come together and line up side by side - crossing over occurs (the chromatids held together by a centromere are no longer identical)
What are the characteristics of an aerobic phase of cellular respiration?
- takes place inside the mitochondrion - dependent upon the presence of oxygen - Preparatory reaction, citric acid cycle, electron transport chain
Telophase I
- the nuclear envelope re-forms and nucleoli reappear - cytokinesis may or may not occur
Initiation
- the step that brings all components of the translation machinery together - required to assemble the small ribosomal subunit, mRNA, initiator tRNA and the large ribosomal subunit for the start of protein synthesis - A large ribosomal subunit joins to the small subunit - 3 binding sites, P (peptide), A (amino acid), E (exit) - Initiator tRNA happens to be capable of binding to the P site (carries only amino acid methionine)
Describe the Citric Acid Cycle
- utilizes oxygen as final acceptor of electrons - Aerobic - cyclical series of oxidation reactions that give off CO2 and produce one ATP - turns twice because two acetyl CoA molecules enter the cycle per glucose molecule - The citric acid cycle accounts for two immediate ATP molecules per glucose molecules
List three characteristics of NAD+
-accepts two electrons plus one hydrogen ion (H+) = NADH -high-energy electrons carried through it to the electron transport chain -Only need a small amount of NAD+, used over and over again
What is the role of electron carriers in cellular respiration?
-it involves many individual metabolic reactions, each one catalyzed by its own enzyme -NAD+ and FAD pick up electrons @ specific points in the cellular respiration pathways and carry these high energy electrons to an electron transport chain in mitochondria, where they drop them off -The empty NAD+ and FAD is then free to go back and pick up more electrons
List two characteristics of FAD
-sometimes used instead of NAD+ -accepts two electrons and two hydrogen ions = FADH2
What is Cellular Respiration?
-the process by which cells release the energy stored within organic molecules such as glucose and use this energy to synthesize ATP molecules.
Oogenesis
1. Meiosis in human females begins in the fetus 2. In the ovaries of the fetus, all of the primary oocytes (diploid cells) begin meiosis but become arrested in prophase I. 3. It finishes the first meiotic division as two cells, each of which is haploid 4. One cell: secondary oocyte, other cell: polar body (nonfunctioning cell), eventually it disintegrates 5. If the secondary oocyte is fertilized by a sperm, it completes the second meiotic division, in which it again divides unequally, forming an egg and a second polar body. 6. The chromosomes of the egg and sperm nuclei then join to form the 2n zygote. 7. If the secondary oocyte is not fertilized by a sperm, it disintegrates and passes out of the body.
Spermatogenesis
1. Spermatogenesis is continual in the testes of human males. 2. Primary spermatocytes are diploid, dividing during the first meiotic division to form two secondary spermatocytes, which are haploid. 3. Chromosomes in secondary spermatocytes are duplicated and consist of two chromatids whereas those in spermatids consist of only one chromatid. 4. Secondary spermatocytes divide during the second meiotic division to produce four spermatids, which is also haploid. 5. Spermatids then mature into sperm
What is the chemical equation for photosynthesis?
6CO2+6H2O--(solar energy)--> C6H12O6+6O2
Explain why DNA replication is called semi-conservative.
A new double strand of DNA is composed of one old strand and one newly synthesized strand
What is pyruvate in cellular respiration?
A pivotal metabolite
Compare and contrast mitosis and cytokinesis in plant and animal cells
Both result in two daughter cells with identical genetic material. - Animal cells form a cleavage furrow between the daughter nuclei, which is constricted by the action of a band actin filaments - Plant cells build a new cell wall between the daughter cells by fusing together vesicles produced by the Golgi apparatus.
How can ATP continue to be produced in the absence of oxygen
By Fermentation
CHAPTER 7
CELLULAR RESPIRATION
Chapter 5
Cell Division
Chapter 25
DNA Structure and Gene Expression
Thylakoid space
Each thylakoid connected to the space of another thylakoid within chloroplast, forming a continuous inner compartment
Identify the electron donation and final acceptor molecules of the electron transport chain
Electron transport chain receives NADH and FADH2 molecules from glycolysis, the preparatory reactions, and the citric acid cycle. It's role is to remove the high-energy electrons from these molecules and then harvesting the energy to form ATP. Oxygen is used in the electron transport chain as a final electron acceptor
Determine the experiments that enabled scientists to determine that DNA made up the genetic material
Griffith (1928) Avery (1944) Hershey and Chase (1952)
Describe why the H+, proton, gradient across the thylakoid membrane is referred to as a storage of energy
H+ ions present in the thylakoid space are at a higher concentration than in the stroma. The tendency is for the ions to move down this electochemical gradient, releasing the stored energy to fuel ATP synthesis
Describe the steps of the process of translation
I. Initiation II. Elongation III. Termination
Describe the effect that gene mutations can have on cells
I. Point Mutation - involve a change in single DNA nucleotide - change alters transcription and possibly changes the specific amino acid II. Base Substitution - a DNA nucleotide being replaced with another incorrect nucleotide - result in wrong amino acid > severely alter protein shape - has little to no effect on the final protein produced : sickle-cell disease (red blood cells become sickle shaped due to base sub in the mRNA codon resulting in decreased blood flow through tiny blood vessels) III. Addition/Deletion - occur most oten because one or more nucleotides are either inserted or deleted from DNA - can be a completely new sequence of codons and nonfunctional protein - sequence of codons - result in frameshift mutation: altering all the codons downstream of point mutation
Summarize the sequence of events that occurs during gene expression
I. Transcription - In eukaryotes, transcription takes place in the nucleus - A portion of DNA serves as a template for mRNA formation - Bases of mRNA are complementary to those of DNA - mRNA is processed before leaving nucleus -> introns are removed II. Translation - Takes place in the cytoplasm - Sequence mRNA bases (complementary to DNA) determines the sequence of amino acids in the polypeptide - tRNA brings attached amino acids to ribosomes - tRNA anticodons pair with codons: amino acid become sequenced in the order originally sequenced by DNA - Proteins determine the structure and function of cells and phenotype of organisms.
Where does glycolysis occur?
Inside the cytoplasm
Distinguish between internal and external controls of the cell cycle.
Internal Signals : control the timing of events, (eg: a protein called Cyclin, like an internal timekeeper) External Signals : like growth factors, tells the cells whether to divide or not.
Sucrose
Molecules that plants use to transport carbohydrates from one part of the plan to the other
Where is fermentation commonly used?
Muscle Cells
What are the low electrons received by?
O2 - which then combines with H+ and becomes water
Describe how oncogenes and mutated tumor suppressor genes work
Oncogenes encode proteins that continuously promote the cell cycle, leading unregulated cell division. Tumor suppressor genes function to inhibit the cell cycle. if mutated, the proteins they express would not be active and the cell cycle would continue, possibly leading to cancer
Describe the structure of a chloroplast from outermost to innermost
Outer membrane->inner membrane->stroma->granum->thylakoid membrane->thylakoid space
CHAPTER 8
PHOTOSYNTHESIS
Describe how the proton gradient is created across the mitochondrial cristae
The carriers of the electron transport chain are located in protein complexes on the cristae of the mitochondria. Each protein complex receives electrons and pumps H+ into the inter membrane space, setting up an electrochemical gradient. When H+ ions flow down this gradient through the ATP Synthase complex, energy is released and used to form ATP molecules from ADP and P. ---> aka chemiosmosis
Griffith (1928)
Streptoccocus Pneumoniae, a strain of pneumonia - smooth strain (S) disease-causing - rough strain (R) non disease- causing +that is if u r exposed to the used mice to eject things in them to see if they die he also boiled the S cells and the mouse lived then he added dead S with the R, the mouse dies RESULT- Griffith proved that there was some sort of genetic transfer between the heat killed S bacteria to the live R bacteria
What is the light reaction?
releases oxygen and provides molecules (in thylakoid membrane)
carotenoids
photosynthesizing cells a yellow-->red color
G3P
product of the Calvin cycle (glucose, sucrose, starch, cellulose, fatty acid, amino acid synthesis)
