Mod 3: Cells

Question 1

What is selective permeability in relation to the plasma membrane?

Answer 1

Some substances, such as lipid-soluble molecules, pass through easily, while others do not

Question 2

What is diffusion?

Answer 2

Involves the movement of particles from an area of higher concentration to an area of lower concentration
(dye tablet in water)

Question 3

What is osmosis?

Answer 3

Involves the diffusion of water down the concentration gradient through a selectively permeable membrane

Question 4

A difference in concentration of a substance from one point to another is called

Answer 4

Concentration gradient

Question 5

A solution with the SAME concentration of solutes as that inside the cell

Answer 5

Isotonic

Question 6

A solution with a HIGHER concentration of solutes as that inside the cell

Answer 6

Hypertonic

Question 7

A solution with a LOWER concentration of solutes as that inside the cell

Answer 7

Hypotonic

Question 8

What would happen to a red blood cell in an isotonic solution?

Answer 8

Cells remain normal in size and water content

Water moves in and out of the cell at an equal rate

Question 9

What would happen to a red blood cell in a hypertonic solution?

Answer 9

Water will diffuse out of the cell, causing it to shrivel and perhaps die

Question 10

What would happen to a red blood cell in a hypotonic solution?

Answer 10

Water will move by osmosis into the cell. This influx of water will cause the cell to swell and eventually burst (called lysis)

Question 11

What is the role of the sodium – potassium pump?

Answer 11

• Regulates the volume of fluid within cells
• provide electrical potential necessary for nervous system activity
• helps in heat protection

Question 12

What happens in the sodium-potassium pump?

Answer 12

• Three sodium ions inside the cell funnel into receptor sites on a channel protein, fueled by ATP, the channel protein releases them into extracellular fluid.
• meanwhile, two potassium ions from outside the cell enter the same channel, the potassium ions are then release inside the cell.
• this keeps the concentration of potassium higher, and the concentration of sodium lower within the cell

Question 13

What is another name for white blood cells? And what is their primary role?

Answer 13

Leukocytes - cells of the immune system that protects the body from infections and foreign invaders

Question 14

What is active transport?

Answer 14

A movement of solutes up the concentration gradient from areas of lesser to greater concentration. (Like swimming upstream, requires energy)

Question 15

What happens in filtration?

Answer 15

Water and dissolved particles are forced across the membrane from an area of higher to lower hydrostatic pressure

Question 16

What is facilitated diffusion?

Answer 16

Helps other molecules move across the membrane

Question 17

What is endocytosis?

Answer 17

The form of vesicular transport that brings substances into the cell
Endo = take in

Question 18

What is phagocytosis?

Answer 18

Occurs when the cell engulfs a solid particle and brings it into the cell
“Cell eating”

Question 19

What is pinocytosis?

Answer 19

Occurs when tiny vacuoles bring droplets of extracellular fluid containing dissolved substances into the cell. The cell then uses the engulfed fluid and nutrients.
“Cell drinking”

Question 20

What is exocytosis?

Answer 20

Uses vesicles to release substances outside of the cell.

Glands often use this method to release hormones

Question 21

What are the building blocks of DNA?

Answer 21

million pairs of nucleotides, each consists of one sugar, one phosphate group, and one of four possible types of nitrogenous bases. 4 bases are adenine, thymine, guanine, cytosine.

Question 22

Why does DNA need help from RNA?

Answer 22

Do you need is too large to leave the nucleus, and protein synthesis takes place in the cytoplasm.

Question 23

What are the 3 forms of RNA that are crucial for protein synthesis?

Answer 23

Messenger RNA, transfer RNA, ribosomal RNA

Question 24

What is transcription?

Answer 24

1st step of gene expression - it involves copying a genes DNA sequence to make an RNA molecule.

Question 25

What is translation?

Answer 25

Once in cytoplasm, mRNA attaches to a ribosome, which consists of rRNA and enzymes. There begins process of being “translated” into a protein. The ribosome moves along the strand of mRNA reading the codons

Question 26

What happens in the first sequence of the cell cycle - first gap phase - G1?

Answer 26

It accumulates the materials it will need to replicate its DNA

Question 27

What happens in the second sequence of the cell cycle (synthesis phase) ?

Answer 27

DNA replication - Cell makes an extra set of DNA

Question 28

What happens in the 3rd sequence of the cell cycle - second gap phase - G2?

Answer 28

Preparation for mitosis. The cell makes final preparations for cell division, including synthesizing necessary enzymes.

Question 29

What happens in the 4th sequence of the cell cycle - mitotic phase?

Answer 29

Cell division occurs

Question 30

What happens in the prophase of mitosis?

Answer 30

Chromosomes appear

Question 31

What happens in metaphase?

Answer 31

Chromosomes line up along the centre of the cell

Question 32

What happens in anaphase?

Answer 32

Chromosomes are pulled to opposite poles by spindle fibres

Question 33

What happens in telophase?

Answer 33

Two new cells are formed