Cells and cell functions

Question 1

What are the advantages of completing the cell cycle in a short amount of time?

Answer 1

Form rapidly
Replace rapidly
Divide rapidly
Replicate rapidly

Question 2

What happens in the synthesis phase of the cell cycle?

Answer 2

DNA is replicated, this prevents genetic abnormalities that can often lead to cell death

Question 3

What happens is mitosis stage of the cell cycle?

Answer 3

DNA division

Question 4

What happens in G1 of the cell cycle?

Answer 4

The cell grows, builds new organelles and builds protein

Question 5

What happens in G2 of the cell cycle?

Answer 5

The cell checks for damage to the DNA and prepares for mitosis by building more protein

Question 6

What are enzymes?

Answer 6

Biological catalysts made of protein

Question 7

What do low temperatures do to the enzymes?

Answer 7

Low temperatures slow the enzymes but doesn’t denature them

Question 8

What is an optimum ph level and temperature?

Answer 8

The certain temperature or ph level that lets the enzymes work most effectively

Question 9

What happens if there’s a higher concentration of enzymes?

Answer 9

There’ll be a quicker reaction

Question 10

What is a monomer?

Answer 10

One unit (e.g amino acids)

Question 11

What does substrate mean?

Answer 11

A reactant

Question 12

What do enzymes do?

Answer 12

Enzymes speed up reactions by breaking down large insoluble molecules into smaller soluble ones

Question 13

What is a tissue?

Answer 13

A group of cells with a similar structure and function

Question 14

What is a stem cell?

Answer 14

An undifferentiated cell that can adapt to fill in any job

Question 15

What are structural components of the body?

Answer 15

Muscles, tendons, bones

Question 16

What is the formula for magnification?

Answer 16

I
                                   A        M
Image = I
Actual = A
Magnification = M

Question 17

What are the components of a human body cell?

Answer 17

Nucleus - contains genetic material that controls activities of the cell

Cytoplasm - where the chemical reactions happen in a cell (contains enzymes)

Cell membrane - holds the cell together and controls what goes in or out

Mitochondria - where the reactions for respiration takes place

Ribosomes - where proteins are made

Question 18

What do plant cells have that human cells don’t?

Answer 18

Cell wall made of cellulose to strengthen cell

Vacuole containing cell sap

Chloroplasts containing chlorophyll for photosynthesis

Question 19

Why are palisade leaf cells adapted for photosynthesis?

Answer 19

Packed with chloroplasts

A lot of surface area is exposed down the side for absorbing CO2

Thin, so you can layer them

Question 20

How are guard cells adapted in plant cells?

Answer 20

When there’s lots of water the guard cells fill with it and go plump, opening the stomata so gases can be exchanged.

When it’s short of water, the guard cells go floppy and close the stomata so water vapour doesn’t escape

They also close at night to save water.

Question 21

what shape is DNA?

Answer 21

A double helix

Question 22

What is a nucleotide?

Answer 22

One strand of DNA

Question 23

what are the complementary base pairings of DNA?

Answer 23

A-T

C-G

Question 24

What is DNA fingerprinting?

Answer 24

Taking a sample of DNA to identify somebody.

Question 25

What is a gene?

Answer 25

a section of DNA that codes for a particular protein

Question 26

What decides the order of amino acids in a protein?

Answer 26

The order of the bases in the DNA

Question 27

How many DNA bases code for an amino acid?

Answer 27

3 bases

Question 28

What is transamination?

Answer 28

When our body changes amino acids into other amino acids based on what we need.

Question 29

How are proteins formed?

Answer 29

The DNA unzips itself and copies itself on to and mRNA strand (a strand that replaces every T with U)

The mRNA moves out of the nucleus and joins with the ribosomes

The ribosomes attach bases to the mRNA strand in 3’s, making amino acids.

Question 30

What is a catalyst?

Answer 30

A substance which increases the speed of a reaction, without being changed or used up in the reaction.

Question 31

What is net movement?

Answer 31

An overall movement (normally in diffusion or osmosis)

Question 32

What three things affect the rate of diffusion?

Answer 32

The distance of diffusion (longer would be slower)

Concentration gradient (faster the bigger gradient)

Surface area (more area, faster diffusion)

Question 33

How do alveoli pass on oxygen?

Answer 33

The blood in the capillaries is high in CO2 and low in oxygen. The alveoli is the opposite.

The cell wall is one cell thick for easy diffusion and the red blood cells pick up more oxygen and diffuse out CO2

Question 34

What is osmosis?

Answer 34

the movement of water across a partially permeable membrane from a high concentration to a low concentration

Question 35

what is a partially permeable membrane?

Answer 35

A membrane with very small holes in it

Question 36

How does osmosis work?

Answer 36

Water flows in both directions, however because there’s a larger concentration on one side, there’s a net (overall) movement of water from one side to the other

Therefore the strong solution of salt will be diluted by the water as there is less water molecules so it’s trying to even up