Q: A DNA sequence reads $$5'\text{-}ATGCGT-3'. $$What is the corresponding mRNA sequence after transcription, and what would be the first amino acid translated?

mRNA: $$5'\text{-}AUGCGU-3'$$, first amino acid: Methionine

Question 1

During Interphase, a cell undergoes various metabolic activities. What would be the most immediate consequence if a cell skipped the S phase entirely?

Accepted Answer

The cell would fail to replicate its DNA, resulting in daughter cells with incomplete genetic material.

Question 2

Which of the following best explains why meiosis, and not mitosis, is used for gamete formation in sexually reproducing organisms?

Accepted Answer

Meiosis reduces the chromosome number by half, ensuring offspring have the correct diploid number after fertilization.

Question 3

During mitosis, how do spindle fibers and centromeres interact to ensure accurate chromosome segregation?

Accepted Answer

Spindle fibers attach to centromeres via kinetochores, pulling sister chromatids apart toward opposite poles during anaphase.

Question 4

Which mechanism during Meiosis I is primarily responsible for generating genetic diversity among gametes?

Accepted Answer

Crossing over between non-sister chromatids during prophase I and independent assortment of tetrads during metaphase I.

Question 5

A scientist observes a cell with homologous chromosomes paired as tetrads along the metaphase plate. Which process is this cell undergoing?

Accepted Answer

Meiosis I

Question 6

If a population is in Hardy-Weinberg equilibrium, what does the term $$2pq$$ represent?

Accepted Answer

The frequency of heterozygous individuals in the population.

Question 7

Which of the following best describes the difference between incomplete dominance and codominance?

Accepted Answer

Incomplete dominance results in a blended phenotype, while codominance expresses both alleles distinctly.

Question 8

How does gene linkage violate Mendel's Law of Independent Assortment, and how can recombination frequency be used to map genes?

Accepted Answer

Linked genes are inherited together unless crossing over occurs; recombination frequency estimates their distance on a chromosome.

Question 9

Which of the following best describes the structure of a DNA nucleotide and its role in forming the double helix?

Accepted Answer

A nucleotide consists of a phosphate group, deoxyribose sugar, and nitrogenous base; nucleotides link via phosphodiester bonds to form antiparallel strands.

Question 10

A DNA sequence reads $$5'	ext{-}ATGCGT-3'. $$What is the corresponding mRNA sequence after transcription, and what would be the first amino acid translated?

Accepted Answer

mRNA: $$5'	ext{-}AUGCGU-3'$$, first amino acid: Methionine

Question 11

Which process allows bacteria to increase genetic diversity without sexual reproduction?

Accepted Answer

Horizontal gene transfer, such as transformation, transduction, and conjugation.

Question 12

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Non-random mating

Question 13

A population of beetles experiences a flood that randomly kills most individuals, regardless of their traits. Which evolutionary mechanism is this an example of, and why are small populations more affected?

Accepted Answer

Genetic drift; small populations are more likely to lose alleles by chance.

Question 14

Which type of selection would most likely result in a population where individuals at both extremes of a trait are favored over the average?

Accepted Answer

Disruptive selection

Question 15

Which of the following is a prezygotic barrier that prevents different species from interbreeding?

Accepted Answer

Temporal isolation, where species breed at different times.

Question 16

Which of the following best explains why transitional forms are rare in the fossil record according to the punctuated equilibrium model?

Accepted Answer

Evolution occurs in rapid bursts separated by long periods of stasis, leaving few intermediate fossils.

Question 17

A population of rabbits grows rapidly when introduced to a new island, but eventually levels off as resources become limited. Which population growth model does this describe, and what happens to birth and death rates as carrying capacity is approached?

Accepted Answer

Logistic growth; birth rates decrease and death rates increase as carrying capacity is reached.

Question 18

Which of the following is an example of a density-independent factor affecting population size?

Accepted Answer

A volcanic eruption that destroys habitat regardless of population density.

Question 19

Why is atmospheric nitrogen ($$N_{2}) $$unusable by most plants, and which soil bacteria make it available?

Accepted Answer

$$N_{2} is $$inert due to its triple bond; nitrogen-fixing bacteria convert it to ammonia ($$NH_{3}) $$usable by plants.

Question 20

Which of the following best describes why energy flows through an ecosystem in one direction, while matter is recycled?

Accepted Answer

Energy is lost as heat at each trophic level, but matter cycles through biotic and abiotic components.

Comprehensive Guidance for Biology 1-2 Final Exam Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards