SB2 Flashcards
Cells and control
1
Q
How do animals grow
A
- Cell division (the cell cycle)
- Cell differentiation
2
Q
What is the cell cycle
A
- Interphase
- Mitosis
- Cytokinesis
3
Q
What happens during interphase
A
- Cell grows in size
- DNA duplicates
- More organelles are made
- Increase in mitochondria and ribosomes
4
Q
What are the stages of mitosis
A
- Prophase
- Metaphase
- Anaphase
- Telophase
5
Q
What happens during prophase
A
- Spindle fibres form
- DNA condenses into chromosomes
- Nuclear membrane disappears
6
Q
What happens during metaphase
A
- Chromosomes and chromosome copies line up in the middle of the cell
7
Q
What happens during anaphase
A
- Spindle fibres pull away chromosomes and chromosome copies to opposite ends of the cell
8
Q
What happens during telophase
A
- New nuclear membrane forms around the chromosomes on opposite ends
9
Q
What happens during cytokinesis
A
- Cell membrane pinches, cells divide
- New cytoplasm forms within the two cells
10
Q
Describe the importance of mitosis in growth, repair and asexual reproduction
A
- Growth - produces new cells
- Repair - replaces dead or damaged cells
- Asexual reproduction - produces offspring that are genetically identical to the parent
11
Q
Describe the features of daughter cells produced by mitosis
A
- Genetically identical
- Diploid
- Identical sets of chromosomes from single parent cell
12
Q
How do plants grow
A
- Cell division
- Elongation
- Cell differentiation
13
Q
Where does elongation occur in plants
A
- Occurs throughout the plant
14
Q
Describe what meristems are
A
- Regions in a plant where mitosis occurs
- Found in tips of shoots and roots
15
Q
How does cancer occur
A
- Change occurs in the cell
- Uncontrollable and rapid cell division
16
Q
Why is cell differentiation important
A
It allows cells to specialise and be dedicated to a specificfunction
17
Q
How do percentile charts help determine growth
A
- Where an organism lies on it shows its growth in comparison to other organisms
- If a bay is on the 50th percentile for weight, its is heavier than 50% and lighter than 50%
18
Q
What is the difference between embryonic and adult stem cells
A
- Embryonic stem cells can differentiate into any type of cell, but are only available at the embryonic stage
- Adult stem cells can differentiate into only blood, skin and bone cells, but are available at all times
19
Q
Benefits of stem cells in medicine
A
+ Create new tissues/organs
+ Less likely to be rejected (if they are directly from patient)
+ Replace damaged cells
20
Q
Risks of stem cells in medicine
A
- Can be rejected
- Can pass on disease
- Viruses can be passed on
- Can start rapidly and uncontrollably dividing
21
Q
Location and function of the cerebrum
A
- Two cerebral hemispheres at the top of the brain
- Speech, vision, memory, movement
22
Q
Location and function of the cerebellum
A
- Back of the brain
- Muscle coordination and balance
23
Q
Location and function of the medulla oblongata
A
- At the bottom of the brain
- Unconscious activities e.g. breathing, heart rate
24
Q
Limitations when treating diseases in the CNS
A
- Blood brain barrier does not allow drugs to reach brain
- Tumour could be buried deep inside
- Not enough understanding of the brain
- Surgery could risk permanent damage
25
Function and features of a sensory neurone
- Connected to a receptor
- Dendrites, Dendrons, Cell body, Axon w/ myelin sheath, Axon terminal
- To pass on information obtained from receptor cells
26
Function and features of a relay neurone
- Rapidly passes impulse from a sensory neurone to a motor neurone
- Dendrites, Cell body, Short axon w/ myelin sheath, Axon terminal
27
Function and features of a motor neurone
- Send electrical impulse to effectors
- Dendrites, Cell body, Axon w/ myelin sheath, Axon terminal
28
What are effectors
- Muscles
- Glands
29
What is the purpose of the myelin sheath
- Prevents electrical impulse from escaping
- Insulates and speeds up neurotransmission
30
How are electrical impulses passed on
- Reaches the end of neurone - synapse
- Stimulates axon terminal to release chemical substances called neurotransmitters
- This is **diffused** across the synapse
- They bind to receptors on dendrites, stimulating a new electrical impulse
31
Name the parts of eye
- Cornea
- Iris
- Pupil
- Lens
- Ciliary muscles
- Suspensory ligaments
- Retina
- Optic nerve
(Can I please look closely so (I can) read optically)
32
What is the function of the cornea
- Helps focus light
- Refracts light
33
What is the function of the iris
- Coloured part of eye
- Controls how much light enters the pupil
34
What is the function of the pupil
- Hole in the eye that allows light to pass through it
35
What is the function of the lens
-Lets light enter the eye
- Focuses light onto the retina
36
What is the function of the ciliary muscles
- Contract/ relax to change the shape of the lens
37
What is the function of the suspensory ligaments
- Tighten/ slacken to change the the shape of the lens
38
What is the function of the retina
- Contains the receptor cells of the eye
39
What is the function of the optic nerve
- Sends information from the eye to the brain
40
What are rod cells
- Receptor cells in the eye
- Detect light intensity
- Work best in dim light
41
What are cone cells
- Receptor cells in the eye
- Detect colour
- Work best in bright light
42
What changes occur so the eye can see distant objects
- Ciliary muscles relax
- Suspensory ligaments tighten
- Lens becomes less round
43
What changes occur so the eye can see closer objects
- Ciliary muscles contract
- Suspensory ligaments slacken
- Lens becomes more round
44
What causes cataracts, what are the effects and how is is it treated
- Protein build up in lens
- Vision is cloudy and obscured
- Artificial lens
45
What causes colour blindness, what are the effects and how is is it treated
- Faulty (red or green) cone cells
- Colours appear differently/ inability to see certain colours
- Untreatable
46
What causes short sightedness, what are the effects and how is is it treated
- Eyeball is too long or cornea is too round
- Light is focused before the retina
- Distant objects are blurry
- Diverging/ Concave lens
47
What causes long sightedness, what are the effects and how is is it treated
- Eyeball is too short or cornea is not round enough
- Light is focused after the retina
- Close objects are blurry
- Converging/ Convex lens
