which cell structure is responsible for efficiently packaging dna into a small volume to fit into the nucleus of a cell and protect the dna structure

HESI RN

Biology Test

1. Which cell structure is responsible for efficiently packaging DNA into a small volume to fit into the nucleus of a cell and protect the DNA structure and sequence?

A. Golgi apparatus
B. Chromatin
C. Smooth endoplasmic reticulum
D. Mitochondria

Correct answer: B

Rationale: The correct answer is B: Chromatin. Chromatin is responsible for packaging DNA into a more compact, dense shape to fit into the nucleus of a cell. This compact packaging helps protect the DNA structure and regulate gene expression. The Golgi apparatus is involved in modifying, sorting, and packaging proteins. The smooth endoplasmic reticulum is involved in lipid metabolism and detoxification. Mitochondria are known as the powerhouse of the cell, producing energy in the form of ATP.

2. Which of the following options is the term used to represent alternative versions of a gene?

A. Alleles
B. Binary fission
C. Heterozygous
D. Homozygous

Correct answer: A

Rationale: The correct answer is A: Alleles. Alleles are different forms of a gene that can exist at a specific locus on a chromosome. They represent variations in a gene's DNA sequence. Choices B, C, and D are incorrect. Binary fission is a form of asexual reproduction in single-celled organisms, while heterozygous and homozygous refer to different combinations of alleles in an individual, not the alternative versions of a gene.

3. Which of the following makes it possible to predict the genotype and phenotype of the offspring of sexual reproduction?

A. Punnett square
B. Chi-square
C. Microscope
D. None of these

Correct answer: A

Rationale: The correct answer is A, Punnett square. A Punnett square is a tool specifically designed to predict the genotype and phenotype combinations of offspring resulting from a particular cross or breeding experiment. It helps in understanding the probability of different genotypes and phenotypes appearing in the offspring. Choice B, Chi-square, is a statistical test used to determine if there is a significant difference between the expected frequencies and the observed frequencies in a study. Choice C, Microscope, is used for viewing tiny structures and organisms, not for predicting genetic outcomes. Choice D, None of these, is incorrect as Punnett square is a valid tool for predicting genetic outcomes in offspring.

4. Proteins are polymers of 20 molecules called:

A. Amino acids
B. Phospholipids
C. Carbohydrates
D. Fatty acids

Correct answer: A

Rationale: Proteins are indeed polymers made up of amino acids. Amino acids are the building blocks of proteins, where each protein has a unique sequence of amino acids that determines its structure and function. Phospholipids, carbohydrates, and fatty acids are not molecules that make up proteins. Phospholipids are the main components of cell membranes, carbohydrates are sugars used for energy and structural purposes, and fatty acids are building blocks of lipids.

5. Which of the following options identifies the products of cell respiration?

A. Water, carbon dioxide, and oxygen
B. Glucose and oxygen
C. Water, carbon dioxide, and adenosine triphosphate (ATP)
D. Water, glucose, and oxygen

Correct answer: C

Rationale: The correct answer is C: 'Water, carbon dioxide, and adenosine triphosphate (ATP).' During cellular respiration, glucose is broken down in the presence of oxygen to produce water, carbon dioxide, and ATP. Choice A is incorrect as oxygen is not a product of cell respiration but a reactant. Choice B is incorrect as it lists glucose and oxygen, which are actually reactants in the process. Choice D is incorrect as glucose is not a product of cell respiration but a substrate that is broken down to release energy.