BIO General Biology Exam Study Guide PDF

BIO: General Biology Exam to Study Guide 8. Cellular Respiration a. Cellular Respiration i. What inputs (starting products) are needed for cellular respiration? What are the outputs (end products) of cellular respiration? How do these inputs & outputs compare...

BIO: General Biology Exam to Study Guide 8. Cellular Respiration a. Cellular Respiration i. What inputs (starting products) are needed for cellular respiration? What are the outputs (end products) of cellular respiration? How do these inputs & outputs compare to the inputs/outputs of photosynthesis? - ii. Within which organelle does cellular respiration take place? - Mitochondria iii. Which organisms use cellular respiration: autotrophs vs heterotrophs? Plants vs animals? - Both autotrophs and heterotrophs. b. Cellular Respiration (Aerobic) i. What are the roles of NADH and FADH2 during the cellular respiration process? - They are electron carriers during cellular respiration. - Electrons added to result in NADH and phosphate added to result in 4 ATP (Net = +2) ii. What are the 3 phases of cellular respiration? Which of the 3 phases produces the most ATP? - Glycolysis - The Citric Acid Cycle (a.k.a Krebs Cycle) - Electron Transport Chain c. Fermentation (Anaerobic) i. How does fermentation differ from cellular respiration? (Think about the environments they operate in.) What are the end products of fermentation? - Fermentation is a biochemical process that gets energy (ATP) from carbohydrates and does not require oxygen. 1. Alcoholic Fermentation: ethanol, carbon dioxide, and NAD+ 2. Lactic Fermentation: lactic acid (lactate) and NAD+ ii. Give examples of food/drinks that result from fermentation. - Ethanol (wine), Hydrogen (farts), lactic acid (cheese), carbon dioxide (bread) 9. Cellular Reproduction a. Genes i. What are genes made of? Where can they be found? What are they used for? - Made of Deoxynucleotide (DNA) - Contained in the chromosomes which are inside the nucleus. - Nucleotide segments of DNA. - Code for making proteins. - Once or more genes can affect traits, e.g. ear lobes. - Traits can produce variation with species. b. DNA Packaging i. What steps are involved in packing DNA into a small nucleus? - A DNA molecule wraps around histone proteins(spools) to form nucleosomes like”beads on a string” in the beginning stages of compacting DNA to fit within a cell’s nucleus. c. Haploid vs Diploid i. What do the terms “haploid” and “diploid” mean? Where do we find haploid cells and diploid cells? - Haploid: * Contain one set (n or 1n) of chromosomes. Seen in gametes, i.e. sperm or egg cells. - Diploid: * Contain two sets (2n) of chromosomes. Are body cells. ii. If given the number of chromosomes in a body cell, how can you determine the number of chromosomes in a sex cell of the same organism? d. The Cell Cycle i. How much of a cell’s “life” is spent in Interphase? What happens in Interphase? - 90% of a cell’s life is spent in Interphase. - G1 phase: - Gathering energy and proteins for making more DNA. - S phase: - DNA replication, resulting in 2 copies of chromosomes. - G2 phase: - Stores more energy and proteins. - Some organelles duplicated. ii. What are the steps of Mitosis? What is happening at each step of Mitosis for: the chromosomes, the mitotic spindle, and the overall cell? - Prophase: the nuclear membrane breaks down and the mitotic spindle begins to form. - Metaphase: chromosomes align on the mitotic spindle. - Anaphase: sister chromatids separate and pull to the opposite pole. - Telophase: nuclear membrane begins to form and a cleavage furrow develops. iii. What happens during Cytokinesis? - Cleavage furrow = site along equator that pulls inward (pinches together) - Microfilaments force the cell membrane to contract (pinch together) and separate the cell into two daughter cells. iv. What is “dinofuzz”? If Sinosauropteryx couldn't fly, what might it have used feathers for? - Dinofuzz = the fluff that surrounded the dinosaur fossil. (simple structure) - Attract mates or keep warm. 10. Sexual Reproduction a. Meiosis i. What are some drawbacks to sexual reproduction compared to asexual repro.? - Lots of energy spent. - Finding and attracting mates. - Forming haploid cells. - Less offspring compared to asexual reproducing species. ii. How are the daughter cells From Meiosis different from the end cells of Mitosis? - Meiosis - Results in 4 genetically unique haploid daughter cells for reproduction. All have half the number of chromosomes that the parent cell had. - Mitosis - Results in 2 genetically similar diploid daughter cells for growth and repair. Both have the same number of chromosomes that the parent cell had. iii. What are the steps of Meiosis I? How does Anaphase I differ from Anaphase II? Meiosis: - Process where somatic diploid cell divides into gamete haploid: one set of chromosomes (G1, S, G2 phase similar to mitosis) - Two rounds of nuclear division (meiosis I and II) 1. Homologous chromosomes separated. 2. Sister chromatids separation. - Results in 4 genetically unique haploid daughter cells. Prophase I: - Membrane around the nucleus breaks apart (the dashed line) - Meiotic spindle begins. (the tubes and the fiber that look like strings) - The meiotic spindle will form a series of tracks to guide migration of the chromosomes. - Formation points (centrosomes) migrate to the poles and tracks begin to form. Crossing-over: - A source of genetic variation in final daughter cells. - Exchange of chromosome segments between non-sister homologous chromatids. - Results in recombinant chromosomes (has contributions from both parents) - Tetrad = set of 4 sister chromatids Metaphase I: - Meiotic spindle is fully formed. - Pairs of homologous chromosomes align along the “equator”. - Chromosomes attach to spindle tracks, poised to separate the pairs. Independent Assortment: - A source of genetic variation. - Many possible arrangements of homologous chromosomes during Metaphase I. - Can result in several possible combinations of chromosomes in final daughter cells. Anaphase I: - Homologous chromosomes are pulled away from the equator. - Sister chromatids stay together. Telophase I: - Chromosomes reach the poles. - The nuclear membrane forms around the chromosomes. Cytokinesis: - Separation into two daughter cells. iv. What processes introduce genetic variation during Meiosis? When do these processes occur? - Crossing-over: after prophase 1 - Independent Assortment: after metaphase 1 b. Nondisjunction i. What is nondisjunction? - An error in chromosome distribution. Occurs during Anaphase 1 or Anaphase 2. - 1: Chromosome pairs fail to separate - all daughter cells will have incorrect number of chromosomes. - 2: Sister Chromatids fail to separate - some daughter cells will have incorrect number of chromosomes. ii. If nondisjunction occurs during Anaphase I, how might the daughter cells be affected? If it occurs during Anaphase II, how are the daughter cells affected? - 1: Chromosome pairs fail to separate - all daughter cells will have incorrect number of chromosomes. - 2: Sister Chromatids fail to separate - some daughter cells will have incorrect number of chromosomes. 11. Patterns of Inheritance a. Pea Plants i. What traits did Mendel observe during his pea plant experiments? - Easy character to study (e.g., pea color, plant height) b. Hybrids i. Beginning with purebred parents (P) for flower colors, what flower colors and ratio were seen in the F1 generation? The F2 generation? - After the first cross, the resulting generation (F1) were all purple. - Not blended colors between purple and white (e.g., no light purple colors) - Subsequent crossing produced a 3:1 ratio of purple to white flowers (F2) - Didn’t matter which parent (P) was purple (male or female), the results were the same. ii. What are alleles? What does it mean to be homozygous or heterozygous? - Mendel developed an hypotheses based on his observation saying that there were alternate versions of genes (alleles) for characters he was observing. - Organisms inherit 2 alleles, one from each parent. - Identical alleles = homozygous; different alleles = heterozygous An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location. iii. How is a dominant allele relative to a recessive allele? - Allele can be dominant or recessive. - Dominant traits continue to be expressed in a hybrid (“they dominate”)  - Recessive traits have no noticeable effect in a hybrid. - These traits don’t disappear. c. Genotype vs Phenotype i. How are genotype and phenotype related? - Genotype: is the genetic make-up of an individual. - Phenotype: is the outward expression of those genes. (ex: eye color, hair color, hair texture, Height, tumb. ii. How could two different genotypes produce the same phenotype? d. Punnett Squares i. If you know the genotype of two parents, can you determine the genotypes of their possible offspring (children)? - Yes. e. Chickenosaurus? i. How does Jack Horner propose to make a small “pet dinosaur”? - By manipulating the genes of a chicken embryo and reversing evolution to bring dinosaur like features. 12. Variations on Mendel’s Laws & DNA a. Variations on Dominance i. How is codominance different from incomplete dominance? - Incomplete Dominance - Heterozygotes appear (phenotype) as a mix between parent appearances. * Red (RR) x White (rr) = Pink (Rr) - Codominance - Both parent alleles are expressed in the phenotype of the offspring. * Red (RR) x White (rr) = Red/White (Rr) ii. What is pleiotropy? - One gene that affects many traits. - Sickle cell anemia can lead to: - Affects the hemoglobin protein and its shape, thus changing the shape of RBCs.  - Also can lead to: retinal detachment (eye vision), liver enlargement and failure, renal failure (kidneys), stroke (brain), heart attack… b. Structure i. Describe the different parts of nucleotides. Where are these parts found within a DNA molecule? - Double helix composed of nucleotides. - Nucleotides come in 2 equal pairs. - Composed of: nitrogen base, phosphate group, and deoxyribose (sugar) - Sugar and phosphate groups form the backbone of each helix (spiral shape) - Nitrogenous bases stick out from the backbone and bond to complementary bases from another helix. ii. How do nitrogenous bases pair off within DNA? i.e. Who pairs with whom? - Pairs of bases form between 1 purine (adenine, guanine) and 1 pyrimidine (thymine, cytosine) - adenine + thymine - guanine + cytosine c. Replication i. Enzymes: What does helicase do? DNA polymerase? DNA ligase? - Helicase (enzyme) splits the helix making a replication fork (y-shape). - DNA polymerase (enzyme) continuously adds base pairs to 3’ end (leading strand) - DNA polymerase adds base pairs in sections (Okazaki fragments) to lagging strands from 3’ direction. - DNA ligase comes by later and binds Okazaki fragments. *Leading Strand (3’ to 5’) and Lagging Strand (5’ to 3’) = Okazaki Fragments = smoosh the molecules together. ii. What is the end result of DNA Replication? - 2 new DNA strands form as an exact copy of the original. 3. Transcription & Translation a. RNA i. Describe two ways RNA is different from DNA. - RNA is a single helix and Uracil is in place of Thymine. * DNA = Deoxyribonucleic Acid * RNA = Ribonucleic Acid b. Transcription i. What are the three phases of transcription? - Initiation - Elongation - Termination ii. What regions within DNA “tell” RNA polymerase where to start and stop? - Initiation tells RNA polymerase to start. - Termination tells RNA polymerase to end. iii. What “post processing” steps are needed before mRNA is ready for translation? - Post-processing in eukaryotes before migrating from nucleus to cytoplasm. - Stabilizing proteins added to prevent degradation. - Caps are added to the ends of mRNA. - Introns are excess nucleotides that are removed. - Exons stay put in mRNA. c. Translation i. What molecules and organelles participate to build a protein? - mRNA and Ribosomes ii. How does translation (as a process) differ from transcription ? What is the role of tRNA? - Translation - uses mRNA to build proteins. - Transcription - makes proteins from genes within DNA. - tRNA interacts with the start codon to begin the process. - The ‘t’ is for “transfer” d. Mutations i. What is a codon? “A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid.” - A stop codon (nonsense mutation) = prematurely ended, incomplete protein. - Codon for the same amino acid as before (silent mutation) = no change to protein. - Codon for different amino acids (missense mutation) = can result in little or big. - Signals the start or end of a protein synthesis. ii. In what ways can bases be changed within DNA to cause a mutation? - A permanent change to the genetic information of a cell or virus. - Some mutations can be beneficial but most are neutral or harmful. - Substitutions: - Replacement of one nucleotide base for another affects the transcription process. - With a new base, the resulting triplet may yield. - Codon for the same amino acid as before (silent mutation) = no change to protein. - Codon for different amino acids (missense mutation) = can result in little or big. iii. What types of mutations result from changes to DNA? - Codon for the same amino acid as before (silent mutation) = no change to protein. - Codon for different amino acids (missense mutation) = can result in little or big. - A stop codon (nonsense mutation) = prematurely ended, incomplete protein. 14. Gene Control a. Gene Regulation i. How do cells containing the same DNA become specialized into different types of cells, e.g. skin cells, bone cells, nerve cells, etc.? - ii. Generally, how are genes regulated? - For many cells with the same DNA to become specialized, the expression of genes must be regulated. - Genes get activated and deactivated (turned on and turned off) - Proteins are created at specific times. b. Gene Regulation in Prokaryotes i. Within prokaryotes, where does transcription take place? Where does translation take place? - Within prokaryotes, transcription and translation occur in the same place (the cytoplasm) and almost simultaneously. - To control gene expression, prokaryotes regulate the transcription step. - Example: lactose (sugar) and lactase (enzyme) * Lactase helps us break down sugar (lactose) - When lactose is present, lactase helps to break down the lactose. - If lactose is absent, we don’t need the lactase. - Operon  - Related genes + sequences that control them. - Ex: Lactase genes + Promoter + Operator ii. How do prokaryotes (e.g., bacteria) control the expression of genes? - To control gene expression, prokaryotes regulate the transcription step. iii. What is the role of a repressor protein? How does it work? - A repressor protein acts as a "brake" on gene expression by binding to specific DNA sequences called operators, which prevents RNA polymerase from accessing the promoter region of a gene, thereby inhibiting transcription and stopping the production of mRNA for that gene, effectively "turning off" the gene expression; essentially, it acts to repress the transcription of a particular gene or set of genes. - To prevent or reduce the expression of specific genes by physically blocking RNA polymerase from binding to the promoter region on DNA. iv. What is an operon? - Operon - Related genes + sequences that control them. - Ex: Lactase genes + Promoter + Operator c. Gene Regulation in Eukaryotes i. Within eukaryotes, where does transcription take place? Where does translation take place? - Because of their complexity and organelles, eukaryotes have multiple ways to regulate gene expression. - Transcription and translation occur in different location (inside the nucleus vs. outside) - Regulating gene expression at different stages: - Epigenetic: when DNA is unwound. - If DNA is tightly packed, no transcription can occur. - Transcriptional: when RNA is transcribed. - “Activator” proteins help ENA polymerase attach to DNA - Post-transcriptional: when RNA is processed and exported to cytoplasm. - How RNA is spliced and how long it “lives” are ways to regulate its function. - Translation: when RNA is translated to protein. - Translation can be interrupted by the presence of select molecules. - Post-translational: protein activation/breakdown. - Some proteins require modifications to activate them. ii. At what stages can genes be regulated? Think about the various steps involved to go from DNA to protein. “Genes can be regulated at any stage of the process from DNA to protein, including transcription (DNA to mRNA), RNA processing (including splicing), translation (mRNA to protein), and post-translational modifications;however, the most common point of regulation is at the initiation of transcription, where the process of copying DNA into mRNA is controlled by regulatory proteins.” d. Reproductive Cloning i. In the example of Dolly the Sheep, what was the role of each of the 3 sheep used in the experiment? What were they each being used for? - Diploid cells from sheep 1 are cultured. - Haploid egg cell (sheep 2) has nucleus removed and replaced from donor 1 cells. - Recombinant egg is stimulated to grow into embargo. - Sheep 1: the nucleus. - Sheep 2: the cell. - Sheep 3: surrogate mother. ii. Which of the 3 sheep was Dolly a clone of? (Don’t just look at the numbers 1, 2, or 3; Dolly was a clone of the sheep that contributed...) - Implantation into surrogate that brings the embryo to tem which will be clone of animal that donated nucleus (sheep 1) - Sheep 1, that has a white face and it contributed cells from its udder. They took the nucleus of Sheep 2 to out and place it with the nucleus of Sheep 1. iii. Was Dolly’s cells haploid or diploid? - Haploid cells (gametes cells)