Topic 1- Cell Biology

Question 1

difference between prokaryotic cell and a eukaryotic cell? 4

Answer 1

prokaryotic cell has no nucleus
Prokaryote is simpler/ smaller

eukaryotic, nucleus with genetic material

Question 2

Magnification equation

Answer 2

Image size/actual size

Question 3

What do both plant and animal have (5)

Answer 3

nucleus
cytoplasm 
cell membrane
mitochondria
ribosomes

Question 4

What is additional in plant cell (3)

Answer 4

chloroplasts
permanent vacuole
cell wall

Question 5

What is a plasmid?2

Answer 5

a circular strand of DNA that floats freely in the cytoplasm

Carry genes that provide genetic advantages
e.g. antibiotic resistance.

Question 6

Nucleus function 2

Answer 6

genetic material

control cellular activities

Question 7

Structure and function of cyptolasm 3

Answer 7

fluid of the cell contains enzymes and nutrients

Chemical reactions take place transport medium

Site of cellular reactions e.g. first stage of respiration

Question 8

Function of cell membrane 1

Answer 8

controls what goes in and out of the cell

Question 9

Function of mitchondria2

Answer 9

Site of later stages of aerobic respiration in which ATP is produced.

Question 10

Function of ribosomes

Answer 10

Joins amino acids in a specific order for protein synthesis

Question 11

function and Vacuole contains 3

Answer 11

contains cell sap
supports cell,
maintaining turgidity

Question 12

cell wall function 3

Answer 12

made of cellulose
strengthens the cell

Prevents the cell bursting when water enters by osmosis.

Question 13

chloroplasts function 2

Answer 13

where photosynthesis occurs. they make the food for the plant

Question 14

Sperm cells adapted and function 4

Answer 14

Haploid nucleus contains genetic information

streamlined head and long tail (swim to egg)

mitochondria provide energy needed for tail movement

Acrosome contains enzymes that digest the egg cell membrane.

Question 15

Muscle cells adapted and function 2

Answer 15

contraction- long so they have space to contract

Mitochondria to provide energy for muscle contraction.

Question 16

Root hair cell function and adaption 2

Answer 16

absorbing water and minerals- big surface area

Large surface area to absorb nutrients and water from surrounding soil.

● Thin walls that do not restrict water absorption.

Question 17

Nerve cells adapted and function 2

Answer 17

rapid signalling- long, branched connections

Long axon allows electrical impulses to be transmitted all over the body from the central nervous system.

Question 18

Xylem adaptations and function 3

Answer 18

transporting water

Thick woody side walls- strengthen structure prevent collapse

long, hollow- route for water to flow

Question 19

Phloem adaptations and function 4

Answer 19

transport food

• sieve plates- dissolved sugars/ amino acids transported up and down
• companion cells provide energy for active transport

Question 20

Importance of cell differentiation

Answer 20

a process where cells become specialized specific to function in the body

Allows production of different tissues and
organs that perform various vital functions in the human body.

Question 21

what is the purpose of cell division in mature animals

Answer 21

repair and replacement of cells

Question 22

differences between electron and light microscope 3

Answer 22

• electron microscope has higher magnification and resolution
• beam of light, beam of electrons
• electrons have shorter wave length=higher resolution

Question 23

how electron microscopy has increased understanding of sub-cellular structures 2

Answer 23

used to study cells in much finer detail enabled to see and understand many more sub-cellular structures

Enable scientists to develop more accurate explanations about how cell structure relates to function

Question 24

define resolution

Answer 24

smallest distance between two objects that can be distinguished

Question 25

how do bacteria multiply

Answer 25

binary fission

Question 26

2 ways bacteria can be grown

Answer 26

nutrient broth solution | colonies in a agar gel plate

Question 27

What is diffusion?

Answer 27

movement of particles from an | area of higher concentration to an area of lower concentration.

Question 28

three main factors affect the rate of | diffusion?

Answer 28

Concentration gradient - larger gradient, faster diffusion. Temperature - higher temperature, faster diffusion Surface area - larger surface area, faster diffusion.

Question 29

substances transported by diffusion in | the lungs and the kidney 2

Answer 29

Lungs: oxygen diffuses into blood from the lungs carbon dioxide diffuses into the lungs from the blood, both down their concentration gradient. Kidney: urea diffuses from cells into blood plasma so it can be excreted in urine

Question 30

How are single-celled organisms adapted for diffusion?

Answer 30

have a large surface area to volume ratio maximises the rate of diffusion of molecules to meet the organism’s needs

Question 31

What four factors increase the effectiveness of a gas exchange surface? 4

Answer 31

Large surface area Thin membrane (short diffusion path) Efficient blood supply (animals) Ventilation (animals)

Question 32

What is osmosis?

Answer 32

The movement of water from a dilute solution to a concentrated solution through a partially permeable membrane diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Question 33

What is meant when a solution is isotonic and hypertonic, hypotonic to a cell?3

Answer 33

iso-concentration of sugar in the external solution is the same as the internal hyper-concentration of sugar in external solution is higher then the internal hypo-concentration of sugar in external is lower than the internal

Question 34

What may happen when an animal cell is placed in a very hypotonic solution?

Answer 34

Water moves into the cell, causing it to burst

Question 35

What may happen when an animal cell is placed in a very hypertonic solution?

Answer 35

Water moves out of the cell, causing it to shrivel up

Question 36

Osmosis in plants 3

Answer 36

If the external solution is more dilute, water will move into the cell and into the vacuole, causing it to swell, causing turgor keeping the leaves and stems of plants rigid). if the external solution is less dilute, water will move out of the cell and they will become soft. Eventually the cell membrane will move away from the cell wall (called plasmolysis) and it will die.

Question 37

What is active transport?2

Answer 37

movement of molecules from a more dilute solution to a more concentrated solution against a concentration gradient, using energy from respiration.

Question 38

How do plant root hair cells use active transport2

Answer 38

take up mineral ions from a more dilute solution in soils. Ions magnesium and nitrates are required for healthy growth

Question 39

How is active transport used to absorb the | products of digestion?2

Answer 39

to transport glucose from a lower concentration in the gut to a higher concentration in the blood. Glucose is then transported to the tissues where it can be used in respiration

Question 40

How is genetic information stored in a prokaryotic | cell?3

Answer 40

Found free within the cytoplasm as: ● Chromosomal DNA (single large loop of circular DNA) ● Plasmid DNA

Question 41

At what point in their life cycle do most animal cells | differentiate?

Answer 41

Early in their life cycle

Question 42

For how long do plant cells retain the ability to differentiate?

Answer 42

Throughout their entire life cycle

Question 43

What are the advantages of light microscopes? (4)

Answer 43

● Inexpensive ● Easy to use ● Portable ● Observe both dead and living specimens

Question 44

Name the two types of electron microscope

Answer 44

Transmission electron microscope (TEM) | Scanning electron microscope (SEM)

Question 45

What is the advantage of electron | microscopes?

Answer 45

Greater magnification and resolution.

Question 46

Why do electron microscopes have a greater | magnification and resolution?

Answer 46

They use a beam of electrons which has a shorter wavelength than photons of light.

Question 47

What are the disadvantages of electron | microscopes? (4)

Answer 47

● Expensive ● Large so less portable ● Require training to use ● Only dead specimens can be observed

Question 48

How do plant leaves and stems remain rigid?

Answer 48

Turgor pressure - water moves in by osmosis, causing the vacuole to swell and the cytoplasm to press against the cell wall.

Question 49

What may happen when a plant cell is placed in a very hypertonic solution?

Answer 49

Water moves out of the cell by osmosis and the vacuole and cytoplasm decrease in size. The cell membrane may pull away from the cell wall, causing the cell to become plasmolysed.