Cells

Question 1

What is the basic structural feature of life on Earth?

Answer 1

Cells

Cells are the fundamental units of life, classified as prokaryotic or eukaryotic.

Question 2

What are the two main types of cells?

Answer 2

Prokaryotic and Eukaryotic

Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells have them.

Question 3

What is the significance of surface area to volume ratio in cells?

Answer 3

It limits cell size and necessitates internal compartments (organelles)

A higher surface area to volume ratio allows for more efficient exchange of materials.

Question 4

What is the function of chloroplasts?

Answer 4

Photosynthesis

Chloroplasts use light energy to synthesize glucose in plant cells.

Question 5

What is the role of mitochondria in a cell?

Answer 5

Site of aerobic cellular respiration and ATP production

Mitochondria are known as the powerhouse of the cell.

Question 6

What is the function of the Golgi apparatus?

Answer 6

Protein packaging and modification

The Golgi apparatus prepares proteins for transport within the cell.

Question 7

What do lysosomes contain and what is their function?

Answer 7

Digestive enzymes for breaking down waste and foreign material

Lysosomes are involved in processes like phagocytosis and apoptosis.

Question 8

What is the primary function of the plasma membrane?

Answer 8

Acts as a selectively permeable barrier

The plasma membrane regulates the movement of substances into and out of the cell.

Question 9

Fill in the blank: The plasma membrane is primarily made of _______.

Answer 9

Phospholipids

Phospholipids form a bilayer that is crucial for membrane structure.

Question 10

What is passive transport?

Answer 10

Movement of molecules without energy use

Passive transport includes processes such as diffusion and osmosis.

Question 11

What are the three types of solutions that affect osmosis?

Answer 11

• Hypotonic solution
• Hypertonic solution
• Isotonic solution

These solutions describe the solute concentration relative to the intracellular environment.

Question 12

What happens to animal cells in a hypotonic solution?

Answer 12

They may burst (lyse)

Water moves into the cell, causing it to swell.

Question 13

What is the role of cholesterol in the plasma membrane?

Answer 13

Regulates fluidity of the membrane

Cholesterol helps maintain membrane integrity across temperature changes.

Question 14

True or False: Ribosomes are classified as organelles.

Answer 14

False

Ribosomes are not membrane-bound and can be found freely in the cytosol.

Question 15

What is the function of the rough endoplasmic reticulum?

Answer 15

Synthesis and modification of proteins

The rough ER is studded with ribosomes and surrounds the nucleus.

Question 16

How is the surface area calculated?

Answer 16

Length x Width x Number of sides

This formula is used to determine the total area of a 3D object.

Question 17

What is the definition of osmosis?

Answer 17

Movement of water across a selectively permeable membrane

Water moves from low solute concentration to high solute concentration.

Question 18

What is the fluid mosaic model?

Answer 18

Describes the structure of the plasma membrane as a flexible layer of lipids with embedded proteins

This model illustrates the dynamic nature of the membrane.

Question 19

What is a hypotonic solution?

Answer 19

A solution with a low solute concentration compared to the intracellular environment of the cell.

Question 20

What happens to animal cells in a hypertonic solution?

Answer 20

Animal cells may become shrivelled.

Question 21

What occurs to plant cells in a hypertonic solution?

Answer 21

Plant cells may become plasmolysed.

Question 22

What characterizes isotonic solutions?

Answer 22

Solutions with equal solute concentration compared to the intracellular environment of the cell.

Question 23

In an isotonic solution, what is the net movement of water?

Answer 23

There is NO net movement of water.

Question 24

What is facilitated diffusion?

Answer 24

Movement of substances assisted by protein carriers or protein channels.

Question 25

Why do ions require protein channels for diffusion?

Answer 25

Ions are repelled by the fatty acid tails of the phospholipid bilayer.

Question 26

What are channel proteins specific to?

Answer 26

Specific ions they are transporting.

Question 27

What types of molecules can carrier proteins transport?

Answer 27

* Amino acids * Glucose

Question 28

What causes a carrier protein to undergo a conformational change?

Answer 28

The binding of a molecule to the protein.

Question 29

What is active transport?

Answer 29

Movement of molecules against their concentration gradient using energy (ATP).

Question 30

What are the two types of active transport?

Answer 30

* Protein mediated (active transport) * Bulk transport

Question 31

What is the role of ATP in active transport using carrier proteins?

Answer 31

ATP provides the energy that causes a conformational change in the carrier protein, allowing it to transport a molecule across the plasma membrane (PM) against its concentration gradient.

Question 32

What is bulk transport?

Answer 32

A form of active transport that moves large or groups of molecules in or out of a cell.

Question 33

What is exocytosis?

Answer 33

Movement of molecules out of the cell in bulk, involving vesicles that fuse with the plasma membrane.

Question 34

What is endocytosis?

Answer 34

Movement of molecules into the cell in bulk, involving the folding of the plasma membrane.

Question 35

Examples of molecules transported through active transport include:

Answer 35

* Ions * Glucose * Amino acids

Question 36

Where does the uptake of glucose occur in humans?

Answer 36

In the intestines.

Question 37

What is the function of root hair cells in plants related to active transport?

Answer 37

Uptake of mineral ions.