Cells Ans The Plasma Membrane

Question 1

Where is cytoplasm found in cells?

Answer 1

In the cell membrane

Question 2

What’s the relationship between the cytoplasm and cytosol?

Answer 2

Cytoplasm = Cell - nucleus 
Cytosol = Cell - (nucleus+organelles

Question 3

What organelle controls the functioning of eukaryotic cells?

Answer 3

The nucleus

Question 4

What is the main molecule in a nucleus and how does it control the cells functioning?

Answer 4

The nucleotide sequences that make up DNA are a “code” for the cell to make hundreds of different types of proteins; it is these proteins that function to control and regulate cell growth, division, communication with other cells and most other cellular functions.

Question 5

What is the function of ribosomes?

Answer 5

They make protein.

Protein is needed for many cell functions such as repairing damage or directing chemical processes. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum.

Question 6

What are the main roles of the endoplasmic reticulum (ER)?

Answer 6

It’s major roles involve the folding and transport of various proteins, specifically carrying them to the Golgi apparatus. Someother proteins, mostly the glycoproteins, move across the ER’s membrane.
Basically, the ER is the transportation system of the eukaryotic cell, and its proteins are contained within it until they are needed to move.

Question 7

What is the role of the Golgi apparatus?

Answer 7

A major function is the modifying, sorting and packaging of proteins for secretion. It is also involved

Question 8

Why can lysosomes be described as recyclers?

Answer 8

Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria.

Question 9

Name the components of the cytoskeleton

Answer 9

microtubules (formed by tubulins),

microfilaments (formed be actins) and intermediate filaments.

Question 10

What is the function of the cell wall?

Answer 10

To help the cell maintain its shape

Question 11

What are the group of organisms that have cell walls called?

Answer 11

Plant cells

Question 12

What would happen if the vacuole filled with water?

Answer 12

The cell would decrease in size

Question 13

How does the shape of a cell affects its surface area to volume ratio?

Answer 13

As the cell increases, the ratio of surface area to weight of the cell decreases. This decreases the efficiency of the rate of diffusion and metabolism of the cells.

Question 14

What are the advantages in having membrane bound organelles?

Answer 14

• cells can concentrate and isolate enzymes and reactants in a smaller volume, thereby increasing the rate and efficiency of chemical reactions.
• cells can confine potentially harmful proteins and molecules in membrane-bound organelles, protecting the rest of the cells from their harmful effects.

Question 15

What are the components of the plasma membrane?

Answer 15

The principal components of the plasma membrane are lipids (phospholipids and cholesterol), proteins, and carbohydrate groups that are attached to some of the lipids and proteins. A phospholipid is a lipid made of glycerol, two fatty acid tails, and a phosphate-linked head group.

Question 16

Why are unicellular organisms more likely to experience bigger chance in their external environment compared with cells in multicellular organisms?

Answer 16

Because there is less amount of cells to modify in unicellular cells compared to multicellular

Question 17

Define diffusion

Answer 17

The movement of molecules from an area of high concentration to an area of low concentration

Question 18

What factors increase the rate of diffusion?

Answer 18

Particle size, temperature, concentration difference and diffusion distance affect the rate of diffusion.

Question 19

How do carrier proteins and channel proteins assist in facilitated diffusion?

Answer 19

Unlike channel proteins which only transport substances through membranes passively, carrier proteins can transport ions and molecules either passively through facilitated diffusion, or via secondary active transport.

Question 20

what happens to the plant cell in a hypertonic solution?

Answer 20

When the plant cell is placed in a hypotonic solution , it takes up water by osmosis and starts to swell, but the cell wall prevents it from bursting

Question 21

If salad greens such as lettuce are left for a period of time, the y become limp. To restore their crispness they can be soaked in cold water. Explain the reason for this.

Answer 21

The reason for this is that water would enter the plant cells via osmosis, in order to make water concentrations equal between the inside of the cell and the external water. This would see the plant cells become turgid, appearing ‘crimped’ and crisp. Plasmolysis would occur if they were left out of water, yeah.

Question 22

Distinguish between active transport and simple diffusion…

Answer 22

Active transport is the transport of material with the use of energy (ATP)

while

Diffusion is the transfer of material from an area of high concentration to an area of lower concentration in the absents of energy (ATP)

Question 23

List the characteristics living things have in common…

Answer 23

Living Things are Composed of Cells:
Living Things Have Different Levels of Organization:
Living Things Use Energy:
Living Things Respond To Their Environment:
Living Things Grow:
Living Things Reproduce:
Living Things Adapt To Their Environment:

Question 24

Define endocytosis

Answer 24

Endocytosis refers to a biological process whereby cells absorb material outside their cell membranes.

Question 25

Define exocytosis

Answer 25

the process by which a cell expels molecules and other objects that are too large to pass through the cellular membrane