Cell Biology

Question 1

What are the two main types of cells?

Answer 1

Prokaryotic and eukaryotic cells.

Question 2

Define a prokaryotic cell.

Answer 2

A prokaryotic cell is a simple, single-celled organism without a nucleus; its genetic material is free-floating within the cell.

Bacteria are examples of prokaryotes.

Question 3

Define a eukaryotic cell.

Answer 3

A eukaryotic cell is a complex cell that contains a nucleus enclosed within membranes and other membrane-bound organelles.

Examples include plant and animal cells.

Question 4

List three structures found in plant cells but not in animal cells.

Answer 4

Cell wall, chloroplasts, and a large permanent vacuole.

Question 5

What is the function of the nucleus in a cell?

Answer 5

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

Question 6

Where does aerobic respiration occur within the cell?

Answer 6

Aerobic respiration occurs in the mitochondria.

Question 7

What is the role of ribosomes in a cell?

Answer 7

Ribosomes are the sites of protein synthesis, where amino acids are assembled into proteins.

Question 8

Describe the function of the cell membrane.

Answer 8

The cell membrane controls the movement of substances into and out of the cell, providing a selective barrier.

Question 9

What is the purpose of the cell wall in plant cells?

Answer 9

The cell wall provides structural support and protection; it is made of cellulose.

Question 10

Explain the function of chloroplasts.

Answer 10

Chloroplasts contain chlorophyll and are the site of photosynthesis, where light energy is converted into chemical energy in plants.

Question 11

What is the role of the permanent vacuole in plant cells?

Answer 11

The permanent vacuole maintains cell rigidity (turgor), stores nutrients and waste products, and helps in the growth of the plant cell.

Question 12

Define cell differentiation.

Answer 12

Cell differentiation is the process by which a cell becomes specialized to perform a specific function.

Question 13

What is a stem cell?

Answer 13

A stem cell is an undifferentiated cell that has the potential to develop into various specialized cell types.

Question 14

Name the process by which cells divide to produce identical daughter cells.

Answer 14

Mitosis.

Question 15

What is the significance of mitosis in multicellular organisms?

Answer 15

Mitosis is essential for growth, tissue repair, and asexual reproduction in multicellular organisms.

Question 16

Define diffusion.

Answer 16

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Question 17

What factors affect the rate of diffusion?

Answer 17

Factors include temperature, concentration gradient, surface area, and the distance over which diffusion occurs.

Question 18

Explain osmosis.

Answer 18

Osmosis is the diffusion of water molecules across a selectively permeable membrane from a region of higher water concentration (or lower solute concentration) to a region of lower water concentration (or higher solute concentration).

Question 19

What is active transport, and how does it differ from passive transport?

Answer 19

Active transport is the movement of substances against their concentration gradient, requiring energy (ATP). In contrast, passive transport (such as diffusion and osmosis) does not require energy and occurs along the concentration gradient.

Question 20

Why are electron microscopes advantageous over light microscopes?

Answer 20

Electron microscopes have a higher resolution and magnification than light microscopes, allowing for more detailed visualization of cell structures.

Question 22

What is cell differentiation?

Answer 22

Cell differentiation is the process by which a cell becomes specialized to perform a specific function.

Question 23

What adaptations do root hair cells have to aid their function?

Answer 23

Root hair cells have long extensions that increase surface area for water and mineral absorption from the soil.

Question 24

Define a stem cell.

Answer 24

A stem cell is an undifferentiated cell capable of dividing to produce either more stem cells or specialized cells.

Question 25

Where are stem cells found in adult humans?

Answer 25

In adult humans, stem cells are primarily found in bone marrow.

Question 26

What is the difference between embryonic stem cells and adult stem cells?

Answer 26

Embryonic stem cells can differentiate into any cell type in the body, while adult stem cells are typically limited to differentiating into cell types of their tissue of origin.

Question 27

List two potential uses of stem cells in medicine.

Answer 27

1. Treating diseases like Parkinson's by replacing damaged cells. 2. Repairing damaged tissues, such as heart tissue after a heart attack.

Question 28

What are meristems in plants?

Answer 28

Meristems are regions in plants containing stem cells that can differentiate into various cell types, allowing for growth throughout the plant's life.

Question 29

Why is there ethical controversy surrounding the use of embryonic stem cells?

Answer 29

The use of embryonic stem cells is controversial because it involves the destruction of embryos, raising ethical concerns about the beginning of human life.

Question 30

What is diffusion?

Answer 30

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.

Question 31

Give an example of a substance that moves into cells by diffusion.

Answer 31

Oxygen diffuses into cells for respiration.

Question 32

What factors affect the rate of diffusion?

Answer 32

The rate of diffusion is affected by temperature, concentration gradient, and surface area of the membrane.

Question 33

Define osmosis.

Answer 33

Osmosis is the diffusion of water molecules across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

Question 34

What happens to a plant cell in a hypotonic solution?

Answer 34

In a hypotonic solution, water enters the plant cell by osmosis, causing it to become turgid (swollen).

Question 35

What is active transport?

Answer 35

Active transport is the movement of substances against their concentration gradient, from a region of lower concentration to a region of higher concentration, using energy from respiration.

Question 36

Give an example of active transport in the human body.

Answer 36

The absorption of glucose in the small intestine is an example of active transport.

Question 37

How do root hair cells use active transport?

Answer 37

Root hair cells actively transport mineral ions from the soil into the plant against the concentration gradient.

Question 38

What is the role of carrier proteins in active transport?

Answer 38

Carrier proteins in the cell membrane bind to specific molecules and use energy to change shape, transporting the molecules across the membrane.

Question 39

How does surface area to volume ratio affect the rate of diffusion?

Answer 39

A larger surface area to volume ratio increases the rate of diffusion, as there is more surface area for substances to diffuse across relative to the cell's volume.

Question 40

Why is osmosis important for plant cells?

Answer 40

Osmosis helps maintain turgor pressure in plant cells, which keeps them rigid and supports the plant structure.

Question 41

How do temperature changes affect the rate of diffusion?

Answer 41

Increasing temperature increases the kinetic energy of particles, leading to a faster rate of diffusion.

Question 42

Why do multicellular organisms need specialised transport systems?

Answer 42

In multicellular organisms, cells are not in direct contact with the external environment, so specialized transport systems are needed to deliver nutrients and remove waste products efficiently.