ATI Biology 3 — Questions and Answers
Question 1: Which type of macromolecule are enzymes primarily composed of?
- Proteins (Correct answer)
- Lipids
- Carbohydrates
- Nucleic acids
Correct answer: Proteins
Most enzymes are proteins folded into specific catalytic shapes.
Question 2: What is the role of the cell membrane's phospholipid bilayer?
- Regulating what enters and exits the cell (Correct answer)
- Producing proteins
- Storing genetic information
- Generating ATP
Correct answer: Regulating what enters and exits the cell
The selectively permeable bilayer controls movement of substances in and out.
Question 3: In a dihybrid cross of two heterozygous parents (AaBb), what is the phenotypic ratio of offspring?
- 9:3:3:1 (Correct answer)
- 3:1
- 1:1
- 1:2:1
Correct answer: 9:3:3:1
A cross of two AaBb individuals yields the classic 9:3:3:1 phenotypic ratio.
Question 4: Which structure contains the genetic material in a eukaryotic cell?
- Nucleus (Correct answer)
- Cytoplasm
- Cell wall
- Vacuole
Correct answer: Nucleus
The nucleus houses and protects the cell's DNA.
Question 5: What gas is released as a byproduct of photosynthesis?
- Oxygen (Correct answer)
- Carbon dioxide
- Nitrogen
- Methane
Correct answer: Oxygen
Photosynthesis splits water and releases oxygen as a byproduct.
Question 6: A cell with 46 chromosomes undergoes meiosis. How many chromosomes does each resulting gamete contain?
- 23 (Correct answer)
- 46
- 92
- 12
Correct answer: 23
Meiosis halves the chromosome number, producing haploid gametes with 23 chromosomes.
Question 7: Which term describes an organism's observable physical traits?
- Phenotype (Correct answer)
- Genotype
- Allele
- Chromosome
Correct answer: Phenotype
Phenotype refers to the expressed, observable characteristics of an organism.
ATI Biology 3
Which type of macromolecule are enzymes primarily composed of?