Pre AP Biology -CELLS 5.1 Cell Cycle: Interphase- MCQ Exam Style Questions -New Syllabus

Pre AP Biology -CELLS 5.1 Cell Cycle: Interphase- MCQ Exam Style Questions – New Syllabus 2025-2026

Pre AP Biology -CELLS 5.1 Cell Cycle: Interphase- MCQ Exam Style Questions – Pre AP Biology – per latest Pre AP Biology Syllabus.

Pre AP Biology – MCQ Exam Style Questions- All Topics

Question

Which of these statements best describes growth in plants?

a. Stems, but not roots, have secondary growth.
b. Primary growth, but not secondary growth, occurs at meristems.
c. Primary growth, but not secondary growth, occurs in all seed plants.
d. Trees and other woody plants have secondary growth but not primary growth.

▶️ Answer/Explanation

Correct Option: c

Detailed solution

Primary growth occurs in $100\%$ of seed plants to increase length.
Secondary growth (thickness) is absent in many herbaceous plants.
Both types of growth actually occur at specialized tissues called meristems.
Woody plants like trees must undergo primary growth before secondary growth.
Secondary growth can occur in both stems and roots of woody species.
Therefore, only primary growth is a universal characteristic of all seed plants.

Question

The driving force that pushes a root through the soil is due primarily to which of these activities?

a. continuous cell division in the root cap at the tip of the root

b. continuous cell division of the apical meristem just behind the root cap

c. elongation of the cells behind the root apical meristem

d. maturation of cells and formation of root hairs after cells elongate

▶️ Answer/Explanation

Detailed solution

The correct answer is c. elongation of the cells behind the root apical meristem.

While the apical meristem produces new cells, it is the Zone of Elongation that provides the physical thrust.
In this zone, cells take up water and expand significantly in length.
This expansion creates a powerful mechanical force that pushes the root tip deeper into the soil.
The root cap (option a) primarily serves to protect the meristem and lubricate the path.
Cell division (option b) increases the number of cells but does not significantly increase length.
Maturation (option d) involves cell specialization and anchoring, not the forward driving force.

Question

Which of these characteristics refers to telomerase?

a. It is often active in cancer cells.

b. It is more active in adult than in embryonic cells.

c. It has telomeres made of RNA.

d. It shortens the ends of chromosomes.

▶️ Answer/Explanation

Detailed solution

The correct option is a.
Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes.
In most normal adult somatic cells, telomerase activity is low or absent, leading to progressive shortening.
However, approximately $90\%$ of cancer cells upregulate telomerase to achieve replicative immortality.
Option b is incorrect because telomerase is naturally more active in embryonic and stem cells.
Option c is incorrect because telomeres are made of DNA; telomerase itself contains an RNA template.
Option d is incorrect because telomerase extends telomeres rather than shortening them.

Pre AP Biology -CELLS 5.1 Cell Cycle: Interphase- MCQ Exam Style Questions -New Syllabus