Biology questions and answers

Name five common parts of animal and plant cells.

Nucleus, cell membrane, cytoplasm, mitochondria, ribosomes.

Name two further features of a plant cell.

Cell wall and chloroplasts.

Describe the function of the nucleus.

The nucleus controls cell activities and contains the cell’s genetic material (DNA).

Describe the function of the cytoplasm.

The cytoplasm is a jelly-like fluid where chemical reactions occur.

Describe the function of the cell membrane.

The cell membrane controls the movement of substances in and out of the cell.

Describe the function of the mitochondria.

Mitochondria are the site of respiration and provide energy for the cell.

Describe the function of the ribosomes.

Ribosomes are responsible for protein synthesis.

Describe the function of the chloroplasts.

Chloroplasts contain chlorophyll and carry out photosynthesis in plant cells.

Describe a specialisation of a sperm cell.

Sperm cells have a tail for mobility and many mitochondria to provide energy for movement.

Describe a specialisation of a nerve cell.

Nerve cells have long extensions (axons) to transmit electrical signals over long distances.

Describe a specialisation of a root hair cell.

Root hair cells have a large surface area for efficient water and nutrient absorption.

Describe a specialisation of a phloem cell.

Phloem cells have companion cells and sieve plates to help transport nutrients in plants.

What is “cell differentiation”?

Cell differentiation is the process by which cells develop specialized structures and functions.

When do most animal cells differentiate?

Most animal cells differentiate early in development.

What are the three forms of equation used to calculate magnification (M), the image size (I), or the actual size of an object (A)?

Magnification= image size/ actual size

What is 1340000 nm expressed in standard form?

1.34 × 10⁶ nm

What is 0.0000001 µm expressed in standard form?

1×10−7 µm.

What is the difference between mm, µm, and nm?

1 mm equals 1000 µm, and 1 µm equals 1000 nm; millimeters are larger than micrometers, and nanometers are smaller.

What is a chromosome?

A chromosome is a structure made of thin strands of DNA that contains genes.

What are genes?

Genes are segments of DNA that code for specific proteins and traits.

In what arrangement are chromosomes found normally?

Chromosomes are normally found in pairs.

How many chromosomes does a human have?

Humans have 46 chromosomes.

What has to happen within the cell before it can divide? (2 steps)

The cell’s DNA replicates, and cell organelles are duplicated.

How many chromosomes will be present in a cell after DNA replication?

DNA replication results in two copies of each chromosome normally being 46 so the cell has 92 chromatids after replication

To where do the chromosomes move during mitosis?

Chromosomes move to opposite poles of the cell.

Mitosis is critical for…

Mitosis is critical for growth, repair, and reproduction.

What is a stem cell?

A stem cell is an unspecialized cell that can differentiate into various cell types.

Describe the function of stem cells in embryos.

Embryonic stem cells differentiate into all cell types necessary for development.

Describe the function of stem cells in plant meristems.

Stem cells in plant meristems allow for growth and regeneration of plant tissues.

What is a potential use of stem cells in medicine?

Stem cells may be used to treat conditions like Parkinson’s disease or spinal cord injuries by replacing damaged cells.