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BIO189 Final Exam 2025 Questions and
Answers
Identify the components of aerobic respiration and its equation. - Correct answer C6H12O6 (glucose) + O2 (oxygen) → CO2 (carbon dioxide) + H2O (water) + 36 ATP Identify the location of Glycolysis. - Correct answer occurs in the cytoplasm of cells What are the reactants and products of Glycolysis? What is the ATP yield?
- Correct answer Reactants: glucose Products: 2 pyruvate, 2 ATP, 2 NAD+ Identify the location of Acetyl CoA. - Correct answer mitochondrial matrix What are the reactants and products of Acetyl CoA formation? What is the ATP yield? - Correct answer Reactants: 2 pyruvate, 2 NAD+, 2 coenzyme a (CoA) Products: 2 Acetyl-CoA, 2 NADH, 2 H+, 2 CO2, 2 ATP Identify the location of the Citric Acid Cycle (Krebs Cycle). - Correct answer mitochondrial matrix What are the reactants and products of the Citric Acid Cycle? What is the ATP yield? - Correct answer Reactants: 2 Acetyl-CoA, 6 NAD+, 2 FAD, 2 ADP Products: 4 CO2, 6 NADH, 6 H+, 2 FADH2, 2 ATP. Identify the location of Oxidative Phosphorylation. - Correct answer inner mitochondrial membrane What are the reactants and products of Oxidative Phosphorylation? What is the ATP yield? - Correct answer Reactants: 2 H+, oxygen, 6 NADH, 2 FADH
Products: H2O and 28 ATP Describe the pathway for the H+ ions and electrons during Oxidative Phosphorylation. - Correct answer As the high-energy electrons are transported along the chains, some of their energy is captured. This energy is used to pump hydrogen ions(from NADH and FADH2) across the inner membrane, from the matrix into the intermembrane space. What is the final electron acceptor in the ETC? - Correct answer Oxygen What powers ATP synthase? - Correct answer H+ ions that flow across the membrane, and/or the gradient. Describe ATP formation in terms of fermentation. - Correct answer The process of producing ATP during fermentation in the absence of oxygen is through glycolysis alone. Why does fermentation of glucose yield less ATP than aerobic respiration?
- Correct answer Fermentation only undergoes glycolysis, which yields 2 ATP, whereas aerobic respiration utilizes acetyl-CoA formation, the Krebs Cycle, and Oxidative Phosphorylation. What are the reactants and products of Lactic Acid fermentation? - Correct answer Reactants: 2 ATP, 2 pyruvate, and 2 NAD+. Products: 2 lactate, 2 NADH+, and 2 ATP What are the reactants and products of Alcoholic fermentation? - Correct answer Reactants: 2 ATP, 2 pyruvate, and 2 NAD+. Products: 2 ATP, 2 CO2, 2 NADH+, and 2 ethanol molecules. What is Erwin Chargaff's rules for base pairing? - Correct answer Bases of the two DNA strands in a double helix pair in a consistent way: A-T and C-G How do we calculate DNA nucleotide composition? - Correct answer The total composition of the DNA sample must be accounted for by the sum of all the bases.
How are the bases different between RNA and DNA? - Correct answer In RNA, thymine is replaced by uracil, making RNA bases A&U and G&C. DNA bases are A&T and G&C. What type of bond hold the DNA base pairs together? - Correct answer hydrogen bonds How can the sequence of bases contribute to the diversity among species?
- Correct answer The sequence of bases in a DNA is called genes, which in turn further produces specific proteins, These proteins are the building blocks of living beings. Each organism's sequence of bases is unique to the organism. No one organism will have exact DNA sequence with another organism. What is the difference between autosomes and sex chromosomes? - Correct answer Autosomes are chromosomes that determine the body's general traits, while sex chromosomes determine an individual's sex. What is the chromosome number and arrangement for the average human male and/or the human female? - Correct answer Females have a pair of X chromosomes (46, XX), whereas males have one X and one Y chromosome (46, XY). What does it mean to be a diploid cell? - Correct answer a cell that contain two copies of each chromosome (2n) What is a haploid cell? - Correct answer a cell that contains one set of chromosomes (n) What is a karyotype? - Correct answer A display of every pair of homologous chromosomes within a cell, organized according to size and shape What kind of information can be inferred from a karyotype? - Correct answer Reveals characteristics of an individual's chromosomes; this can help identify genetic problems or chromosomal abnormalities. What are the functions of the enzymes for DNA replication (Helicase, Ligase, DNA polymerase, Primer)? - Correct answer Helicase: Unwinds the double helix by breaking hydrogen bonds
Ligase: Enzyme that seals breaks in double-stranded DNA DNA Polymerase: Assembles a new strand of DNA based on the sequence of a DNA template Primer: Short, single strand of DNA that base-pairs with a targeted DNA sequence What is the semiconservative model? - Correct answer Type of DNA replication in which the replicated double helix consists of one old strand, derived from the parental molecule, and one newly made strand. What are the steps of DNA replication? - Correct answer 1. The original strand of DNA is unzipped by an enzyme that breaks the hydrogen bonds between the bases.
- Free nucleotides start to attach to their base pair by forming new hydrogen bonds. (A goes to T, T with A, C with G, and G with C)
- Another type of enzyme connects these nucleotides into a chain.
- This process continues until the entire strand of DNA has been unzipped and copied. What is the result of DNA replication? - Correct answer Two identical strands of DNA What would a DNA strand look like as RNA after transcription? - Correct answer The new mRNA is a copy of the gene from which it was transcribed. What is a mutation? - Correct answer any change in the DNA sequence What causes nucleotide dimers? - Correct answer Exposure of cells to UV light from the sun causes covalent bonds to form between adjacent bases resulting in dimers making a kink in the DNA double helix What is a gene? - Correct answer a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
What are DNA codons? - Correct answer a sequence of three nucleotides that correspond with a specific amino acid, as well as issue a start or stop signal during protein synthesis. What is DNA translation? - Correct answer the process of decoding the mRNA into an amino acid chain How do each of the components in DNA translation work together to translate the mRNA? - Correct answer - mRNA is transcribed in the nucleus.
- In the cytoplasm, a small ribosomal subunit binds to mRNA.
- Initiator tRNA base pairs with the first mRNA codon.
- Large ribosomal subunit joins the small subunit.
- Ribosome assembles a polypeptide chain.
- Translation ends when the ribosome encounters a stop codon. What are the functions of mRNA, tRNA, and rRNA? - Correct answer mRNA is used as a messenger that copies the DNA code that can leave the nucleus and bring a "blueprint" for a particular protein to the ribosome. tRNA is used as a transfer molecule that carries free-floating amino acids to the ribosome. rRNA makes up ribosomes. How does the genetic code work in translation? - Correct answer It is rewritten. the sequence of nucleotides in the mRNA is "translated" into a sequence of amino acids in a polypeptide (protein chain). Explain the results of the types of mutations - Correct answer A substitution mutation replaces one base with another, resulting in a change in only one chemical letter. A missense mutation is when a nucleotide gets changed, resulting in a different amino acid in the protein. A nonsense mutation is the worst type of substitution mutation. This type of mutation occurs when a base change causes an early stop codon. This
causes the protein to be too short and almost always results in a non- functioning protein. A silent mutation is when a single base pair gets swapped out on the DNA, but the mutated RNA sequence produces the same amino acid. A frameshift mutation is produced either by the insertion or deletion of one or more new bases. How can mutations be beneficial? - Correct answer Mutations lead to genetic diversity. Genetic diversity provides variations in organisms that could lead to better fitness in an environment. How do environmental factors affect gene expression? - Correct answer Methylation is influenced by environmental factors encountered during an individual's lifetime. For example, exposure to cigarette smoke alters DNA methylation in a person's cells. Chemicals in the smoke change the methylation of certain promoters in a pattern that also occurs in cancer cells What are some of the benefits of using cell lines to study human diseases?
- Correct answer helps in possibly finding cures to diseases and cancers Compare and contrast cytoplasmic division in plants and animals. - Correct answer In animal cells, a contractile ring pinches the cytoplasm into two parts. A cleavage furrow produces and deepens until the cytoplasm is pinched into two. Each new cell has its own nucleus, and cytoplasm, and is enclosed by a plasma membrane. In plant cells, microtubules guide vesicles from Golgi bodies and the cell surface to the division plane. Vesicles and their wall-building contents fuse into a disk-shaped cell plate. The cell plate grows and forms a cross wall between the two new nuclei. The cell plate develops into two new cell walls, separating the descendant cells. What happens to the microtubules in animal and plant cells during cytoplasmic division? - Correct answer microtubules extend outward from duplicated centrosomes to form the mitotic spindle
What is happening at each stage of mitosis? - Correct answer Prophase - chromosomes condense and DNA becomes visible Metaphase - chromosomes line up in the center of the cell Anaphase - Chromatids break apart at the centromere and move to opposite poles. Telophase - Two nuclei formed after nuclear envelopes reform around each group of chromosomes. What is happening at each stage of meiosis? - Correct answer Prophase I
- crossing over, homologous chromosomes pack tightly, and the nuclear envelope breaks up. Metaphase I - homologous chromosome pairs align midway, and microtubules attach chromosomes. Anaphase I - homologous chromosomes separate and move to opposite spindle pools, random assortment, chromosome number reduces. Telophase I - complete set of chromosomes cluster at each spindle pole, nuclear envelope forms, chromosome packing loosens, and two haploid cells form when the cytoplasm divides. Prophase II - chromosomes pack tightly, spindle microtubules assemble and bind to sister chromatids, and the nuclear envelope breaks up. Metaphase II - chromosomes align midway, microtubules attach chromosomes to opposite spindle poles. Anaphase II - sister chromatids separate and move to opposite spindle poles, as the chromatids separate, each becomes an individual chromosome. Telophase II - complete set of chromosomes at each spindle pole, nuclear envelope forms around each chromosome as chromosomal packing loosens, four haploid cells form when the cytoplasm divides. Aerobic vs. Anaerobic - Correct answer Aerobic - Complete breakdown of glucose, Carbon dioxide and water are end products, and uses oxygen in chemical breakdown. Anaerobic - Partial breakdown of glucose, lactic acid is the by-product, and it doesn't need oxygen in the chemical breakdown.
Explore the ethical, medical, and historical ramifications for the study and use of HeLa cells - Correct answer HeLa cells are widely used to investigate cancer, viral growth, protein synthesis, effects of radiation, and many other processes important in medicine and research. Describe the movement of the chromosomes in the stages of the cell cycle.
- Correct answer They move towards the poles rather than the poles toward the chromosomes gametes vs somatic cells - Correct answer Gametes: haploid (1/2 the chromosomes) sex cells Somatic Cells: diploid (full set of chromosomes) body cells What are gametes and how are they produced? - Correct answer Gametes are sex cells (egg and sperm). They are produced through meiosis Explain the differences between sexual (meiosis) and asexual reproduction (mitosis). - Correct answer Sexual reproduction requires two parents, allows for genetic diversity for better survival, and beneficial mutations spread quickly through the process of meiosis. Asexual reproduction requires one parent and produces a genetic clone through the process of mitosis. Explain the consequences of mutations in the cell cycle. - Correct answer can disrupt the cell cycle process, leading to genetic disorders or cancer. Oncogenes - Correct answer genes that cause cancer by blocking the normal controls on cell reproduction Characteristics of metastasis. - Correct answer Malignant cells travel through the blood or lymphatic system and invade other tissues and organs to form a secondary tumor. Often metastasis has occurred prior to diagnosis. Characteristics of malignant cells. - Correct answer -Rapid growth -Irregular -Rarely contained within a capsule
Genotype vs. Phenotype - Correct answer An organism's genotype is the set of genes that it carries. An organism's phenotype is all of its observable characteristics Codominance vs. incomplete dominance - Correct answer Codominance - both alleles show up in the phenotype (ex. black and white speckled chickens) Incomplete Dominance - a mixed phenotype is observed (ex. grey chickens) ABO blood groups - Correct answer Genetically determined classes of human blood that are based on the presence or absence of carbohydrates A and B on the surface of red blood cells. The ABO blood group phenotypes, also called blood types, are A, B, AB, and O. Examples of polygenic and pleiotropic inheritance. - Correct answer With polygenic inheritance, multiple genes influence. With pleiotropy, one gene influences multiple traits. Examples of polygenic inheritance: skin color and height Examples of pleiotropy inheritance: Sickle Cell Disease What is nature vs. nurture? - Correct answer Genetic vs. environment- producing traits or behaviors Environmental factors that affect phenotype. - Correct answer diet and exercise, sunlight and water, temperature Causes of continuous variation - Correct answer genetics and environment How are pedigrees used to study human inheritance patterns? - Correct answer - Shows whether a trait is associated with a dominant or recessive allele
- Shows whether a trait is on an autosome or sex chromosome What are the effects of nondisjunction? - Correct answer extra chromosome or missing chromosome
What are autosomal dominant inheritance patterns? - Correct answer Each affected person usually has an affected parent; occurs in every generation (heterozygotes and homozygotes) What are autosomal recessive inheritance patterns? - Correct answer Both parents of an affected person are carriers; not typically seen in every generation (homozygotes) Achondroplasia inheritance - Correct answer inherited in an autosomal dominant manner Klinefelter Syndrome - Correct answer A genetic condition in which a male is born with an extra copy of the X chromosome. Turner Syndrome - Correct answer A chromosomal disorder in females, in which one of the X chromosomes (sex chromosomes) is missing or partially missing. Down Syndrome - Correct answer a condition of intellectual disability and associated physical disorders caused by an extra copy of chromosome 21. Explain why X-linked recessive disorders are more common in men than in women. - Correct answer a male must inherit only one allele to be affected by the disorder; a female must inherit two, and inheriting two disorder- causing alleles is statistically less likely than inheriting one. Color-blindness inheritance - Correct answer Red-green color blindness is inherited in an X-linked recessive pattern. Punnet Square Method - Correct answer Construction of a simple diagram as a way to predict probable outcomes of a genetic cross.
