Test 2 (Mitosis, Plasma Membrane)

Question 1

What is mitosis?

Answer 1

Mitosis is the dividing, and thus, reproduction of cells

Question 2

What are the stages of mitosis?

Answer 2

• Prophase
• Metaphase
• Anaphase
• Telophase
• Cytokinesis

Question 3

What are the stages of the cell cycle?

Answer 3

• Interphase (G1, S, G2)

- Mitosis (prophase, metaphase, anaphase, telophase, cytokinesis)

Question 4

What happens during interphase?

Answer 4

• Growth 1: Cell carries out metabolism and regular activities
• Synthesis: The cell replicates all of the DNA in the nucleus
• Growth 2: The cell prepares for mitosis

Question 5

What occurs at each step of mitosis?

Answer 5

• Prophase: DNA condenses around histone proteins, creates chromosomes, called supercoiling
• Metaphase: Chromosomes line up at the equator of the cell
• Anaphase: Chromatids are pulled to the poles of the cell
• Telophase: Nuclear envelope comes back, DNA uncoils, cleavage furrow forms
• Cytokinesis: Cell divides along cleavage furrow

Question 6

What is diploid number?

Answer 6

The fully paired sets of chromosomes in a cell, represented as 2n

Question 7

What is haploid number?

Answer 7

Single set of unpaired chromosomes in a cell, represented as n

Question 8

What is equational division?

Answer 8

The same amount of DNA is in each of the daughter cells as the parent cell had

Question 9

What is the mitotic index?

Answer 9

Ratio between number of cells in mitosis and total number of cells. Found by dividing number of cells in mitosis by total number of cells obvserved

Question 10

What are intrinsic proteins?

Answer 10

They are integral proteins. They go all the way through the membrane

Question 11

What are extrinsic proteins?

Answer 11

They are the peripheral proteins. They are only attached to the outside of the membrane, sometimes go part way through

Question 12

What is the sugar side chain used for?

Answer 12

It is used in cell recognition

Question 13

What is cholesterol used for?

Answer 13

It is used to restrict the movement of the membrane. It reduces the fluidity and the permeability of the membrane

Question 14

What is diffusion?

Answer 14

It is the passive movement of particles from a region of high concentration to a region of low concentration until equilibrium is reached

Question 15

What is a hypotonic solution?

Answer 15

The solution has a lower solute concentration than inside the cell. This causes water to rush into the cell, which may cause the cell to burst, known as cytolysis

Question 16

What is a hypertonic solution?

Answer 16

The solution has a higher concentration of solute than inside the cell. This causes water to rush out of the cell, which may cause the cell to shrink, known as plasmolysis

Question 17

What is simple diffusion?

Answer 17

When substances move through the phospholipid molecules in the membrane

Question 18

What is facilitated diffusion?

Answer 18

The cell uses channel proteins to help the substances pass through (each channel can only let in 1 substance) and the substance still goes from high to low concentration

Question 19

What is a phospholipid?

Answer 19

Basic components of biological membranes. They are amphipathic, meaning that one side is hydrophilic, the other hydrophobic

Question 20

What is active transport?

Answer 20

Movement of substances across the membrane using ATP. It can move substances across the concentration gradient

Question 21

What is a phospholipid?

Answer 21

Basic components of biological membranes. They are amphipathic, meaning that one side is hydrophilic, the other hydrophobic

Question 22

What is ATP?

Answer 22

It is made of ADP and an inorganic Phosphate molecule

Question 23

What is the structure of sodium-potassium pumps?

Answer 23

In the centre of the pump, there is 2 bonding sites, one for the sodium, the other for the potassium. Depending on the state, the Na+ or K+ ions will be discharged into the cell, and the other will bind

Question 24

What is a potassium channel?

Answer 24

Used in neurons, they allow K+ ions to exit the cell. They have a ball and chain they will open and close the channel

Question 25

What is the Davson-Danielli model?

Answer 25

It is just the phospholipid bilayer with a layer of protein on it on both sides. The evidence showed there to be a light space between 2 dark lines from electron micrographs

Question 26

What is the Singer-Nicolson model?

Answer 26

It is the same thing as the fluid mosaic model. Freeze fracture electron micrographs showed there to be globular proteins in the centre of the bilayer. It was proved with the fusion of red and green tagged membranes.