B1: Cell Biology

Question 1

What are the subcellular structures found in an animal cell and a plant cell?

Answer 1

nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

Question 2

What are the subcellular structures ONLY found in a plant cell?

Answer 2

cell wall, permanent vacuole, chloroplasts

Question 3

What is the function of the nucleus?

Answer 3

controls the activities of the cell and contains the genetic material

Question 4

What is the function of the cytoplasm?

Answer 4

jelly like substance, which is where most chemical reactions take place

Question 5

What is the function of the cell membrane?

Answer 5

controls the passage of substances into and out of the cell

Question 6

What is the function of the mitochondria?

Answer 6

where aerobic respiration takes place

Question 7

What is the function of the ribosomes?

Answer 7

where proteins are synthesised

Question 8

What is the function of the cell wall?

Answer 8

made of cellulose, strengthens the cell

Question 9

What is the function of the permanent vacuole?

Answer 9

filled with cell sap, which supports the plant

Question 10

What is the function of the chloroplasts?

Answer 10

absorbs light to make glucose through photosynthesis

Question 11

What are the two main types of cell?

Answer 11

prokaryotic and eukaryotic

Question 12

What are examples of eukaryotic cells?

Answer 12

plant, animal and fungal cells

Question 13

What is an example of a prokaryotic cell?

Answer 13

bacterial cells

Question 14

What are the differences between prokaryotic and eukaryotic cells?

Answer 14

Prokaryotic cells are smaller, the genetic material is not enclosed in a nucleus and is a single DNA loop and there may be one or two smaller rings of DNA (plasmids), they do not contain mitochondria or chloroplasts

Question 15

What do plasmids allow bacterial cells to do?

Answer 15

move genes from one cell to another

Question 16

What subcellular structures are found in a typical bacterial cell?

Answer 16

plasmid DNA, chromosomal DNA, flagella, cell wall (not made of cellulose), cytoplasm

Question 17

What is the typical size of a plant cell?

Answer 17

0.1mm

Question 18

What is the typical size of an animal cell?

Answer 18

0.02mm

Question 19

What is the typical size of a prokaryotic cell?

Answer 19

0.002mm

Question 20

What is the definition of resolution?

Answer 20

the ability to see two or more objects as separate objects

Question 21

What does a light microscope allow you to see?

Answer 21

plant, animal and bacterial cells

Question 22

What doesn’t a light microscope allow you to see?

Answer 22

subcellular structures

Question 23

What does an electron microscope pass through the specimen? As a result, what does it give?

Answer 23

electrons, a much higher resolution

Question 24

What can be seen through an electron microscope?

Answer 24

structures inside mitochondria and chloroplasts so scientists can study how they work, ribosomes and their role in making proteins can be studied

Question 25

What is the definition of magnification?

Answer 25

how many times larger the image is than the real object

Question 26

What sort of sort of cell division do bacterial cells use?

Answer 26

binary fission

Question 27

How frequently bacterial cells divide?

Answer 27

as frequently as once every 20 minutes if they have enough nutrients and a stable temperature

Question 28

Why do cultures of microorganisms need to be uncontaminated?

Answer 28

so specific strains can be used to test the effects of antibiotics or disinfectants

Question 29

In school and college labs, what temperature should cultures be incubated at?

Answer 29

25°C to reduce the likelihood of the growth of harmful bacteria

Question 30

Why will higher temperatures of incubation be used in industry?

Answer 30

for more rapid growth

Question 31

What is the cell cycle?

Answer 31

the series of changes that cells go through including growth and division

Question 32

What is mitosis?

Answer 32

cell division that forms two daughter cells, each with the same number of chromosomes as the parent cell

Question 33

What does a cell need to do before it divides?

Answer 33

grow and increase the number of subcellular structures like ribosomes and mitochondria, then, the DNA replicates to form two copies of each chromosome (genetic material is doubled)

Question 34

What are the steps of mitosis?

Answer 34

1. Parent cell with two sets of chromosomes
2. Each chromosome replicates itself
3. Chromosomes line up along the centre of the cell, divide and the copies move to opposite poles
4. Each ‘daughter’ cell has the same number of chromosomes, and contains the same genes as the parent cell

Question 35

Why is cell division by mitosis important?

Answer 35

• growth and development of multicellular organisms
• repairing damaged tissues
• asexual reproduction

Question 36

What is a stem cell?

Answer 36

a human embryo cell or adult bone marrow cell that has yet to differentiate

Question 37

What can embryonic cells differentiate to form?

Answer 37

all types of cells

Question 38

What can adult stem cells differentiate to form?

Answer 38

only certain cells e.g blood cells

Question 39

What is therapeutic cloning?

Answer 39

a cloned embryo of the patient may be used as a source of stem cells

Question 40

Why is therapeutic cloning beneficial?

Answer 40

the stem cells won’t be rejected

Question 41

Why are some people concerned about the use of cloned embryos?

Answer 41

• there may be risks, like the transfer of viral infections
• they may have ethical or religious obligations

Question 42

Where are stem cells in plants found?

Answer 42

meristems

Question 43

Why could the cloning of plant stems cells be useful?

Answer 43

• rare species can be cloned to protect from extinction
• large numbers of identical crop plants with special features (such as disease resistance) can be made

Question 44

What is diffusion?

Answer 44

the net movement of particles from an area of high concentration to an area of low concentration until they are evenly spread out

Question 45

What factors affect the rate of diffusion?

Answer 45

difference in concentration (concentration gradient), temperature, surface area of the membrane

Question 46

How are surfaces and organ systems specialised for exchanging materials?

Answer 46

large surface area, thins surface so that molecules only have to diffuse are short distance, surfaces are kept moist so that substances can dissolve and diffuse across cell membranes faster, in animals , a rich blood supply maintains the concentration and ventilation occurs to speed up gaseous exchange

Question 47

What is osmosis?

Answer 47

the diffusion of water form a dilute solution to a concentrated solution through a partially permeable membrane

Question 48

What is active transport?

Answer 48

moves substances against a concentration gradient (area of high to low concentration) requiring energy from respiration

Question 49

Where does active transport occur in plants?

Answer 49

mineral ions being absorbed into plant root hairs from very dilute solutions in the soil

Question 50

Where does active transport occur in animals?

Answer 50

sugar molecules being absorbed from lower concentrations in the gut into the blood