Topic 1 - Cell biology

Question 1

What are prokaryotic cells, e.g.

Answer 1

Simpler, smaller cells
bacteria

Question 2

What are eukaryotic cells, e.g.

Answer 2

More complex cells
Animal and plant

Question 3

Cell membane job

Answer 3

Hold cell together and control what enters and leaves the cell

Question 4

Cytoplasm job

Answer 4

Jelly like substance where most chemical reactions take place

Question 5

How nerve cells are adapted (3)

Answer 5

• Long axon allows impulses to be transmitted all over the body from the CNS
• Dentrites (branched connections) conect to other nerve cels and form netwroks around the body
• Myelin sheath insulates axon and speeds up transmission of impulses

Question 6

Importance of differentiation

Answer 6

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

Question 7

How often do bacteria multiply and in what conditions

Answer 7

Once every 20 mnutes when there are enough nutrients and it is warm

Question 8

3 main cell cycle stages

Answer 8

1) Replication
2) Mitosis
3) Division of cells

Question 9

Equation for time in phase of mitosis

Answer 9

Observed no. of cells at stage
—————————————— x total time of cell cycle
Total number of cells

Question 10

Define magnification

Answer 10

Number of times bigger an image appears compared to size of real object

Question 11

How does an electron microsope work

Answer 11

• Beams of electrons focused ysing magnets
• Electrons hit fluorescent screen
• Visible light is emitted
• Image is produced

Question 12

What is prokaryotic cell wall mafe of

Answer 12

Peptidoglycan

Question 13

Define reolution

Answer 13

Smallest distance between two objects that can be distinguished

Question 14

Where are genes

Answer 14

In chromosomes

Question 15

What has to happen before mitosis

Answer 15

• Cell grows and increases subcellular structures
• DNA then dublicated and forms x shape chromosomes
• Each arm is an exact double

Question 16

What does dilute mean

Answer 16

Solution has less solute

Question 17

What 2 places is DNA stored in prokaryotic cells

Answer 17

Plasmids
single loop of circular DNA

Question 18

What are plasmids and their role

Answer 18

Small O loop of DNA
Carry genes that provide genetic advantages

Question 19

4 ways sperms adapted

Answer 19

Streamline head to swim faster
Long tail to help swim to egg
Mitochondria in head for optimal energy
Contains enzyme that digests the cell membrane of an egg

Question 20

2 ways muscle cells have adapted

Answer 20

• Long for space to contract
  
  • Lots of mitochondria to generate energy needed for contraction

Question 21

2 root hair cell adaptations

Answer 21

• Large surface area to absorb nutrients and water from surrounding soil
• Lots of mittochondria for active transport

Question 22

What is defferentiation

Answer 22

Process by which cells become specialised

Question 23

How do light microscopes work

Answer 23

-Beam of light passed through eypiece lens allowing specimen to be observed

Question 24

4 advantages of light microscopes

Answer 24

• Inexpensive
• Easy to use
• Portable
• Observe ded and living specimins

Question 25

Disadvantage of light microsopes

Answer 25

Limited resolution

Question 26

Advantage of electron microsope

Answer 26

Greater magnification and resolution

Question 27

How electron microsopes help cel knowledge

Answer 27

Allows for subcelllar strutures to be observed in detail

Question 28

4 diadvantages of electron microscope

Answer 28

- Expensive - Large soless portable - Require specialist training - Only dead specimins can be observed

Question 29

Magnification euation

Answer 29

image/object ## Footnote * * *

Question 30

How does bacteria multiply

Answer 30

binary fission

Question 31

Why steralise petri dish and culture medium before use

Answer 31

to kill any bacteria already present

Question 32

Why pass incolating loop through bunsen burner

Answer 32

Kil any bacteria on the loop

Question 33

Why secure petri dish with tape and store upside down

Answer 33

- Stop bacteria in air contaminating - Not fully taped so can have O₂ for aerobic respiration - Upside down so condensation doesnt form

Question 34

Incubation temperature at school and why

Answer 34

25⁰ as any higher, harmful pathogens would grow

Question 35

Number of bacteria adfter 3 hours for population that divides every 15 minutes with 5 to begin

Answer 35

15m = 0.25h 3/0.25 = 12 5 x 2¹²= 20480

Question 36

Whats a stem cell

Answer 36

An unspecialied cell capable of differentiating into other cel types and of self-renewal

Question 37

2 things embryonic stem cells can treat

Answer 37

paralysis diabetes

Question 38

Where are adult stem cells

Answer 38

bone marrow

Question 39

where are plant stem cells

Answer 39

meristem

Question 40

Describe mitosis (6)

Answer 40

* Chromosomes libe up at the centre of the cell * Spindle fibres pull them apart * 2 arms of each chromosome go to oppposite ends of the cell * Membrane forms around the new set of chromosomes * These become the nuclei of 2 new cells * Cytopasm and cell membrane divide into 2, providing 2 identical daughter cels *

Question 41

Describe bnary fission (4)

Answer 41

- Circular DNA strands and plasmids replicate - Cell gets biger and DNA strands move to the opposite poles of the cell - Cytoplasm begins to divide and a new cell wall forms - Cytoplasm divides and 2 daughter cells with one cpy of singl strand of DNA and varied number of plasmids produced

Question 42

Example of active of transport in humans e.g.

Answer 42

Gut, where theres lower concentration of nutrients than in the blood, where they need to be

Question 43

1 mm in micro and nanometres

Answer 43

1000 micrometres 1000**_000 nanometres_**

Question 44

Permanent vacuole structure and job

Answer 44

contains cel sap, made of a weak solution of salt and sugar supports cell and hold turgidity

Question 45

What are chromosomes

Answer 45

Coiled up lengths of DNA molecules

Question 46

What does a large membrane to surface area do to diffusion rate and why

Answer 46

increase it as more particles can pass through at once

Question 47

What is the cell cyle

Answer 47

Series of 3 stages during ehich a cell divides

Question 48

Mitochondria

Answer 48

Where most aerobic respirations happen

Question 49

Ribosomes

Answer 49

Wherw protein synthesis happens

Question 50

Cell wall

Answer 50

Rigid and made of cellulose suport the cell

Question 51

Chloroplasts

Answer 51

Contains chlorophyll to absorb light for photosynthesis

Question 52

5 organelles in bacteria

Answer 52

Cell wall Cel membrane cytoplasm single strand of DNA Plasmids

Question 53

organelle not in bacteria

Answer 53

Mitochondria

Question 54

Were are chromosomes

Answer 54

In the nucleus

Question 55

What do genes do

Answer 55

Control development of different characteristics

Question 56

How many copies of each chromosome do body cells have and where are they from

Answer 56

2 mother and father

Question 57

How many pairs pof chromosomes in humans

Answer 57

23

Question 58

What is mitosis

Answer 58

Stage of cell cyle when cell divides

Question 59

Why is mitosis done

Answer 59

To grow or replace damaged cells

Question 60

What does chromosome pair 23 determine

Answer 60

sex

Question 61

What is chromosome pair 23 if male

Answer 61

What does it mean if chromosome pair 23 is XY

Question 62

What is chromosome pair 23 if female

Answer 62

What does it mean if chromosme 23 is XX

Question 63

What is diffusion

Answer 63

Spreading out of particles from higher to lower concentration

Question 64

What states does diffusion happen in and why

Answer 64

Solutions and gases as they are both free to move about randomly

Question 65

Relationship between concentration gradient and diffusion rate

Answer 65

Bigger CG the faster the rate of diffusion

Question 66

How does temperature affect diffusion rate and why

Answer 66

Increases as more energy so particles move faster

Question 67

What molecules can diffuse through membrane + 4 examples

Answer 67

Very small O₂, Glucose, H₂O, amino acids

Question 68

2 molecules that can't diffuse through membrane

Answer 68

Startch and proteins

Question 69

What is osmosis

Answer 69

Movement of water molecles accross a semi-permiable membrane from a region of higher water concentration to lower water concetration

Question 70

What is the division of prokaryotic cells called

Answer 70

Binary fission

Question 71

What is a solute

Answer 71

The substance that is dissolved

Question 72

What is a solvent

Answer 72

The substance in which the solute dissolves

Question 73

What is a hypertonic solution + what will happen to cell + why

Answer 73

Concentration gretaer outside the cell that inside Animal cells become shrivvled plant cells become plasmolised

Question 74

What is a hypotonic solution + what will happen to cell + why

Answer 74

Solutio is lower outside cel than inside the cell Animal cell bursts : lysis Plant cell beocmes turgid

Question 75

What is a isotonic solution + what will happen to cell + why

Answer 75

Solution concentration inside and outside of the cell are the same Animal cells beocme flacid plant cels become flacid

Question 76

Why can't root hair cells use diffusion to get minerals

Answer 76

Conc of minerals is higher in cell than soil, so minerals would be moving out of the plant

Question 77

What is active transport

Answer 77

The movement of particles throgh a semi permiable membrane agains the concentration gradient, from an area of low to high concentration using energy `