B1

Question 1

What is the equation for magnification ?

Answer 1

Image size / real size

Question 2

How many of each are in a metre?
Centimetre, millimetre, micrometre, nanometre

Answer 2

100cm in a 1m
1000mm in 1m
1000000ųm in 1m
1000000000nm in 1m

Question 3

How does a light microscope work?

Answer 3

Use light and lenses to form an image of a specimen and magnify it

Question 4

How do electron microscopes work?

Answer 4

Uses electrons instead of light to form an image

Question 5

Which microscope is better? And why?

Answer 5

Electron microscopes because they have a higher magnification and resolution so can see smaller internal structures

Question 6

What is a prokaryotic cell?

Answer 6

A bacteria cell

Question 7

What is a eukaryotic cell?

Answer 7

A plant or animal cell

Question 8

How are prokaryotic and eukaryotic cells structurally different?

Answer 8

Eukaryotic contain a nucleus which holds genetic information whereas prokaryotic have no nucleus, they contain a single loop of dna and plasmids to hold genetic information

Question 9

What three things does a plant cell have that animal cells don’t?

Answer 9

Cell wall, vacuole and chloroplasts

Question 10

What is the function of all sub-cellular structures?

Answer 10

Nucleus: controls the cell
Cell membrane: controls what goes in and out of the cell
Cytoplasm: where most chemical reactions happen
Mitochondria: where aerobic respiration takes place
Ribosomes: where protein synthesis takes place
Cell wall: supports and strengthens cell
Chloroplasts: contain chlorophyll which absorbs sunlight for photosynthesis
Vacuole: contains cell sap

Question 11

What is the cell wall made of?

Answer 11

Cellulose

Question 12

What is the function of the sperm cell?

Answer 12

Reproduction

Question 13

What is the function of a nerve cell

Answer 13

Rapid signalling

Question 14

What is the function of a muscle cell?

Answer 14

Contraction

Question 15

What is the function of red blood cell?

Answer 15

Transporting oxygen

Question 16

What is the function of root hair cell?

Answer 16

Absorbing water and minerals

Question 17

What is the function of palisade cell?

Answer 17

Absorb sunlight for photosynthesis

Question 18

What is the function of phloem and xylem cells?

Answer 18

Transporting substances

Question 19

How is the sperm cell specialised?

Answer 19

Lots of mitochondria: gives energy
Long flagellum: able to swim
Enzymes: eat away egg in order to fertilise it

Question 20

How is the nerve cell specialised?

Answer 20

Branches: connect to skin cells
Long: form network to send signals

Question 21

How is the muscle cell specialised?

Answer 21

Long: allows space to contact
Lots of mitochondria: more energy to contact

Question 22

How is the red blood cell specialised?

Answer 22

No nucleus: more space to carry oxygen
Large surface area: able to absorb oxygen

Question 23

What are stem cells?

Answer 23

Cells that can differentiate into other cells

Question 24

Where are stem cells found?

Answer 24

Animal: embryos or bone marrow
Plant: meristem tissue (roots and shoots)

Question 25

What cells can each stem cell turn into?

Answer 25

Embryotic cells can turn into any type of cell Bone marrow stem cells can turn into white blood cells, red blood cells and platelets Meristem can turn into any sort of plant cells

Question 26

What is meant by therapeutic use of stem cells?

Answer 26

The use of stem cells to treat diabetes or paralysis

Question 27

How does therapeutic use of stem cells work?

Answer 27

1.skin cell from patient and egg cell from donor 2. Nucleus removed from skin cell then implanted into egg cell 3. Egg cell develops into embryo by mitosis 4. Stem cells removed from embryo and placed in Petri dish 5. Stem cells differentiate into needed cell, e.g. pancreatic cells

Question 28

Advantages of stem cell use

Answer 28

Cure serious disease Improve mental health

Question 29

Disadvantages of stem cell use

Answer 29

Embryo discarded (ethical issues) not thoroughly tested Expensive

Question 30

What is chromosome?

Answer 30

Coiled up length of dna, contain genetic information

Question 31

How many chromosomes does an adult cell have?

Answer 31

23 pairs (46)

Question 32

What is the stage where the cell divides called?

Answer 32

Mitosis

Question 33

Why does mitosis occur?

Answer 33

Growth and repair, replacement of damaged cells

Question 34

What are the steps of the cell cycle?

Answer 34

1. DNA replication 2. chromosomes line up in centre and pulled apart to opposite poles by cell fibres 3. Nucleus, cytoplasm, cell membrane divide (mitosis) 4. Two identical daughter cells are formed

Question 35

What is binary fission?

Answer 35

Single cell division that happens within bacteria (prokaryotic cells) and occurs rapidly

Question 36

How long does binary fission take?

Answer 36

20 minutes

Question 37

What is meant by diffusion?

Answer 37

the spreading out/movement of particles from an area of high concentration to an area of low concentration

Question 38

What is meant by osmosis?

Answer 38

the movement of water molecules from an area of high water concentration to low water concentration, across a partially permeable membrane.

Question 39

What is meant by active transport?

Answer 39

The movement of particles from an area of low concentration to an area of higher concentration using energy.

Question 40

Factors that effect the rate of diffusion

Answer 40

Concentration gradient Temperature Surface area

Question 41

How are organ specialised for exchanges substances?

Answer 41

Having a large surface area A thin membrane - short diffusion distance Having a good blood supply Being ventilated (gas exchange)

Question 42

What is magnification?

Answer 42

The number of times bigger the image appears compared to the size of the real object

Question 43

What is resolution?

Answer 43

The smallest distance between two objects that can be distinguished

Question 44

What to wear can bacteria be grown?

Answer 44

Nutrient broth solution colonies on agar gel plate

Question 45

What nutrients are required for bacteria to grow?

Answer 45

All nutrients including nitrogen carbohydrates and other minerals

Question 46

What are uncontaminated cultures of microorganisms needed for?

Answer 46

Investigating disinfectant and antibiotic action

Question 47

What happens during the preparation of uncontaminated culture?

Answer 47

Use pre-sterilised plastic petri dishes Poor the sterile agar into the petri dish and let it set Sterilise the inoculating loop by passing it through a Bunsen burner Dip the inoculating loop into the solution of microorganisms and add to surface of agar Put the lid on the Petri dish and security with tape and store upside down Incubate the culture at 25°

Question 48

Why must petri dishes be sterilised before use?

Answer 48

To kill any bacteria present

Question 49

Why must inoculating loops be sterilised?

Answer 49

To kill any bacteria present

Question 50

Why must petri dishes be secured with tape?

Answer 50

Stop bacteria in the air contaminating the culture The lid is not fully sealed to prevent the growth of anaerobic bacteria in lack of oxygen

Question 51

Why must petri dishes be stored upside down?

Answer 51

To prevent condensation from forming and dripping down onto the bacteria colonies

Question 52

Why are cultures incubated at 25°?

Answer 52

Harmful pathogens are less likely to grow at this temperature

Question 53

What does active transport require that diffusion and osmosis does not?

Answer 53

Energy from respiration