UCI Bio 93 Final Actual Exam Questions with Correct

pg. 1 UCI Bio 93 Final/ Actual Exam Questions with Correct Verified Answers/ Updated – Rated A+

What are the four most common elements in living matter? - ANSWER - Hydrogen, Oxygen, Nitrogen, and Carbon --make up 96% of all living matter.

What are the subphases of mitosis? - ANSWER - Prophase, Pre-metaphase, Metaphase, Anaphase, and Telophase.

How many checkpoints are there in the cell cycle? - ANSWER - 3 -- G1 checkpoint, G2 checkpoint, and the M checkpoint.

What is a Karyotype? - ANSWER - A layout of Metaphase chromosomes matched with their homologous pairs.

What is a diploid cell? - ANSWER - A cell with 46 chromosomes -- somatic cells.

What is a haploid cell? - ANSWER - A cell with 23 chromosomes -- sex cells.

What is co-dominance? - ANSWER - When two alleles affect the phenotype in distinguishable ways. Ex: blood type -- Ia and Ib are both dominant over i. Therefore, Ia and Ib are co-dominant to i.

What is pleiotropy? - ANSWER - When one gene affects more than one phenotype. Ex: sickle cell anemia produces multiple symptoms (symptoms would be equivalent to phenotypes).

What is epistasis? - ANSWER - When a gene at one locus alters the expression of a gene at another locus.Ex: gene 1 determines black or brown coat color and gene 2 determines if pigment is deposited.

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pg. 2 What is polygenic inheritance? - ANSWER - When multiple genes affect a phenotype and phenotypes are in a range or spectrum. This range is called a normal distribution. Most likely phenotype = immediate phenotype and the least likely phenotype = the extreme phenotype. Shaped like a bell curve -- immediate in middle with high peak and extreme on both ends.

What can impact the phenotype of an organism? - ANSWER - Environment (ex: hydrangeas -- the acidity of the soil determines their color no matter their alleles), diet, epigenetics, etc.

What does the mesoderm give rise to? - ANSWER - the notochord (similar to a spinal chord).

What does the endoderm give rise to? - ANSWER - the digestive tract.

What does the ectoderm give rise to? - ANSWER - the nervous system (brain)/neural plate.

If 2n = 18, how many chromosomes come from the mother? - ANSWER - 9 -- half from mom and half from dad

Meiosis - ANSWER - Meiosis is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them.

What two structures does the chiasma connect? - ANSWER - Non-sister chromatids.

What are the steps of meiosis? - ANSWER - Prophase I, Metaphase I, Anaphase I, Telophase I & cytokinesis (then a second set of phases)

What does meiosis 1 deal with? - ANSWER - homologous chromosomes.

What happens in prophase 1? - ANSWER - The chromosomes condense, the nuclear envelope breaks down, chromosomes cross over, and meiotic spindle forms.

What happens in metaphase 1? - ANSWER - the pairs of homologous chromosomes are now tightly condensed and coiled and become arranged on the metaphase plate. 2 / 3

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What happens in anaphase 1? - ANSWER - the pairs of chromosomes are pulled apart by the spindle fibers (microtubules).

What happens in Telophase 1 and cytokinesis? - ANSWER - The homologous chromosome pairs complete their migration to the two poles as a result of the action of the spindle. Now a haploid set of chromosomes is at each pole, with each chromosome still having two chromatids. A nuclear envelope reforms around each chromosome set, the spindle disappears, and cytokinesis follows.

What happens during meiosis 2? - ANSWER - sister chromatids separate.

What happens in prophase 2 of meiosis? - ANSWER - A new spindle forms around the chromosomes.

What happens in metaphase 2 of meiosis? - ANSWER - Metaphase 2 chromosomes line up at the equator.

What happens in anaphase 2 of meiosis? - ANSWER - Centromeres divide chromatids move to opposite poles of the cells.

What happens during telophase 2 of meiosis? - ANSWER - A nuclear envelope forms around each set of chromosomes and the cytoplasm divides.

What makes meiosis a unique form of cell division - ANSWER - Synapsis and crossing over -- occurs in prophase 1, pairing up of homologous chromosomes, homologous chromosomes cross over and exchange corresponding genetic information (the DNA exchanged contain the same genes, but may have different alleles).

How does meiosis increase genetic variability? - ANSWER - Independent assortment (meiosis 1 -- homologous chromosomes separate independently), crossing over (genetic recombination, prophase 1), and random fertilization (any egg can join with any sperm -- most effective way to obtain genetic variability).

What is the law of segregation? - ANSWER - Alleles coding for the same trait separate independently during gamete formation.

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