MCAS Practice Test Questions and
Answers 2024/2025
A barley plant has 14 chromosomes in its diploid cells. At a particular stage in its life
cycle, the barley plant produces haploid cells (gametes).
Identify the expected number of chromosomes in a haploid cell of a barley plant. -
ANSWER-7 chromosomes
A cellular process is shown in the diagram below. (DNA replication) - ANSWER-New
DNA molecules are being produced.
A composter speeds up the decomposition of dead plant material. The illustration below
shows a person putting plant material into a composter. - ANSWER-Carbon dioxide is
released to the atmosphere.
Describe how the two gases are exchanged between the structure you identified in part
(b) and the capillaries. - ANSWER-oxygen will diffuse in cap and carbon dioxide will
diffuse in the alveoli
Describe what a barley plant uses the haploid cells for and explain why the cells must
be haploid for this purpose. - ANSWER-the Barley plant will use haploid cells for
fertilization with another cell which has to be haploid since both cells contribute to the
chromosome count
During dry years on a remote island chain, small seeds become rare while large seeds
in hard shells remain fairly abundant. The large seeds in hard shells can be eaten only
by birds with large beaks.
Which of the following best describes how natural selection will most likely affect seed-
eating birds on the island chain during an extended dry period? - ANSWER-Birds with
large beaks will produce more offspring than birds with small beaks.
Explain why the branching of the air passageways in the lungs is important for efficient
respiratory system functioning. - ANSWER-branching allows more surface area for the
air passage way and thinner walls; important for diffusion in capillaries
Fructose is a simple sugar that can be a source of energy for the body. What type of
organic molecule is fructose? - ANSWER-carbohydrate
How can adaptation help an animal from it's prey. - ANSWER-They can easily
camouflage; changing fur can hide from predators, survive and reproduce
Identify and generally describe the cellular process by which the haploid cells are
produced. - ANSWER-meiosis: m1, m2 split to form four haploid cells from the original
diploid cell
Answers 2024/2025
A barley plant has 14 chromosomes in its diploid cells. At a particular stage in its life
cycle, the barley plant produces haploid cells (gametes).
Identify the expected number of chromosomes in a haploid cell of a barley plant. -
ANSWER-7 chromosomes
A cellular process is shown in the diagram below. (DNA replication) - ANSWER-New
DNA molecules are being produced.
A composter speeds up the decomposition of dead plant material. The illustration below
shows a person putting plant material into a composter. - ANSWER-Carbon dioxide is
released to the atmosphere.
Describe how the two gases are exchanged between the structure you identified in part
(b) and the capillaries. - ANSWER-oxygen will diffuse in cap and carbon dioxide will
diffuse in the alveoli
Describe what a barley plant uses the haploid cells for and explain why the cells must
be haploid for this purpose. - ANSWER-the Barley plant will use haploid cells for
fertilization with another cell which has to be haploid since both cells contribute to the
chromosome count
During dry years on a remote island chain, small seeds become rare while large seeds
in hard shells remain fairly abundant. The large seeds in hard shells can be eaten only
by birds with large beaks.
Which of the following best describes how natural selection will most likely affect seed-
eating birds on the island chain during an extended dry period? - ANSWER-Birds with
large beaks will produce more offspring than birds with small beaks.
Explain why the branching of the air passageways in the lungs is important for efficient
respiratory system functioning. - ANSWER-branching allows more surface area for the
air passage way and thinner walls; important for diffusion in capillaries
Fructose is a simple sugar that can be a source of energy for the body. What type of
organic molecule is fructose? - ANSWER-carbohydrate
How can adaptation help an animal from it's prey. - ANSWER-They can easily
camouflage; changing fur can hide from predators, survive and reproduce
Identify and generally describe the cellular process by which the haploid cells are
produced. - ANSWER-meiosis: m1, m2 split to form four haploid cells from the original
diploid cell
