ATDH - Admission Test for Dental Hygiene Cellular and Molecular Biology Questions and Answers

Question 1

Which of the following best describes the primary outcome of meiosis?

Accepted Answer

Four haploid cells that are genetically different from the parent cell.

Answer

Meiosis is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell and from each other. This is in contrast to mitosis, which produces two genetically identical diploid cells.

Question 2

A patient has a genetic disorder that prevents their cells from properly synthesizing proteins. A defect in which organelle would most directly cause this issue by failing to 'read' the mRNA transcript?

Accepted Answer

Ribosome

Answer

The ribosome is the cellular machinery responsible for translation, the process of synthesizing a protein from an mRNA template. The ribosome reads the codons on the mRNA strand and facilitates the linking of amino acids brought by tRNA to form a polypeptide chain. A defect in ribosomes would directly impair protein synthesis.

Question 3

In the fluid mosaic model of the cell membrane, what is the primary function of integral proteins?

Accepted Answer

To transport molecules across the membrane and act as receptors.

Answer

Integral proteins are embedded within the phospholipid bilayer and play crucial roles as channels or transporters for substances that cannot freely diffuse across the membrane, such as ions and glucose. They also function as receptors for cell signaling.

Question 4

During DNA replication, one enzyme is responsible for unwinding the double helix by breaking the hydrogen bonds between the nucleotide base pairs. Which enzyme performs this critical function?

Accepted Answer

DNA Helicase

Answer

DNA Helicase is the enzyme that 'unzips' the two strands of the DNA double helix, creating the replication fork where replication can begin. DNA Polymerase then synthesizes the new strands, and DNA Ligase joins fragments together.

Question 5

A cell needs to move calcium ions from the cytoplasm, where the concentration is low, into the sarcoplasmic reticulum, where the concentration is high. This process requires energy. Which mechanism of cellular transport is being used?

Accepted Answer

Active Transport

Answer

Active transport is the movement of substances across a cell membrane against their concentration gradient (from a region of lower concentration to a region of higher concentration). This process requires cellular energy, typically in the form of ATP. The other options are forms of passive transport, which do not require energy.

ATDH - Admission Test for Dental Hygiene Practice Test

ATDH - Admission Test for Dental Hygiene Practice Test

ATDH - Admission Test for Dental Hygiene Cellular and Molecular Biology Questions and Answers