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biology > P1B2 - Cells and control > Flashcards

P1B2 - Cells and control Flashcards

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1
Q

What is Mitosis?

A

Cell divison which produces 2 identical daughter cells from 1 parent cell.

Mitosis produces clones and all cells will have 2 sets of chromosomes (diploid - 46)

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2
Q

What happens during mitosis? The stages?

A

1 Prophase : Nucleus membrane breaks down.
Spindle fibres r formed

2 Metaphase : Chromosomes line up along the middle of the cell attached to spindle fibres

3 Anaphase : The two sets of chromosomes are pulled to opposite ends of the cell

4 Telophase : 2 new nucleis are formed around each set of chromosome

  1. Cytokinesis : Cell surface membrane are formed splitting into 2 new identical daughter cells
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3
Q

What does the cell cycle consist of?

A

Interphase
Mitosis
Cytokinesis

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4
Q

What is a malignant tumour?

A

Malignant tumours can invade neighbouring tissues and spread throughout the body in the blood, leading to secondary tumours.

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5
Q

What is a benign tumour?

A

Benign tumours stay in a specific part of the body, often within a membrane.

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6
Q

What is cancer?

A

A group of diseases

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7
Q

What are the 3 regions of growth?

A

Cell division
Elongation
Differentiation

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8
Q

What is differentiation?

A

The process where a cell develops new sub-cellular structures to let it perform a specific function.

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9
Q

What is a stem cell?

A

Undifferentiated cells.

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10
Q

Features of a stem cell

A

Can become any type of cell
Can create more stem cells

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11
Q

How can using stem cell be a form of treatment?

A

Stem cells may be able to replace damaged cells in the body and treat it. E.G. Type 1 diabetes

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12
Q

What is therapeutic cloning?

A

A process that produces (creates) an embryo with the same genes as the patient.

This is ideal for use in stem cell medical treatments.

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13
Q

What are the steps for therapeutic cloning?

A

A body cell is taken from patient. The nucleus is separated from cell

Nucleus from patients cell is fused w an empty egg cell from donor

The cells are stimulated to divide and develop into an embryo

The body will not reject the cells and stem cells are available for therapeutic use

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14
Q

What are some disadvantages of stem cells?

A

Could transfer viral infections
Ethical beliefs
Rejection - Patients immune system rejects and destroy the new cells.
Can cause cancer

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15
Q

What is the Central Nervous System made up of? Whats made up of neurones?

A

Brain
Spinal cord
The peripheral nervous system is made up of neurones.

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16
Q

What do axons and dendrites do?

A

Axons carry electrical impulses away from the cell body while dendrites carry it towards.

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17
Q

What is a synapse?

A

Gaps between neurones

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18
Q

What do neurones do?

A

Neurones (nerve cells) carry electrical impulses between receptors, the CNS and effectors.

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19
Q

What do reflex actions do?

A

Reflex actions allow us to respond to dangerous situations rapidly and automatically. Reflex actions do not involve conscious thought.

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20
Q

The order of components in the reflex arc?

A

Stimulus
Receptor
Neurones
Effector
Response

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21
Q

What is a stimulus

A

Stimulus - Changes in environment causing a response ( detected by receptor )

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22
Q

What is a receptor?

A

Receptor - Detects the change in the environment and starts a signalling process within the body. ( Signal is picked up by a neurone )

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23
Q

What are the 3 neurones?

A

The Sensory neurone - carries the signal in the form of an electrical impulse to the CNS

The Relay neurone (in CNS) - relays the electrical impulse from the sensory neurone to the motor neurone.

The Motor neurone - carries the electrical impulse from the CNS to an effector.

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24
Q

What is an effector?

A

A muscle or gland that brings an action in response to a change in the environment.

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25
Q

What happens in the reflex arc?
(unconscious reactions)

A

The stimulus is detected by a receptor.

The sensory neurone carries the signal from receptor to spinal cord.

A relay neurone returns the signal/impulse, missing out the brain.

The motor neurone transmits impulses to effectors (muscles or glands).

An effector brings about an action in response.

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26
Q

Why is it hard to treat brain injuries?

A

Delicate
Not well understood
Complex

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27
Q

What are the 3 parts of the brain?

A

Medulla oblongata
Cerebellum
Cerebral cortex

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28
Q

What is the function of the Medulla oblongata? (connected to spinal cord)

A

This part is responsible for unconscious activities (e.g. breathing and heartbeat).

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29
Q

What is the function of the Cerebellum? (back of brain)

A

Muscle coordination
The cerebellum is important for movement, posture, balance and speech.

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30
Q

What is the function of the Cerebral cortex? (front of brain)

A

80% of the brain
This part is responsible for conscious thought (e.g. memory, language and intelligence).

31
Q

What are ways to scan the brain?

A

CT scans - Xrays brain
PET scans - Uses radioactive glucose

32
Q

What are brain tumours and how can they be treated?

A

Brain tumours are lumps of dividing cancer cells.

Can be treated with chemotherapy (using drugs), radiotherapy (using radiation) or cutting it out.

33
Q

What is the cornea?

A

The transparent frontal part of the eye that refracts light.

34
Q

What is the sclera in the eye?

A

The white of the eye is the opaque protective outer layer.

35
Q

What is the optic nerve in the eye?

A

Sends visual information (as electrical impulses) from the retina to the brain.

36
Q

What is the retina?

A

Full of receptor cells, which are sensitive to both the brightness (light intensity) and the colour of light

37
Q

What is the pupil?

A

A hole in the centre of the iris, through which light passes to get to the retina.

38
Q

What does the iris do?

A

Controls the quantity of light reaching the retina

39
Q

What are the ciliary muscles in the eye?

A

A ring of smooth muscle that can change the shape of the lens, which the eye uses to focus light

40
Q

What is the suspensory ligament in the eye?

A

A ring of fibres that connect ciliary muscles to the lens

41
Q

What happens when your eye focuses on a close object?

A

Lens - Thickening and rounding.
Ciliary muscles - Contracting
Suspensory ligaments - Loosening.

42
Q

What happens when our eye focuses on a far object?

A

Minor refraction of light rays
Ciliary muscles relax
Lens become flatter and thinner
Suspensory ligaments tighten

43
Q

What do glasses do?

A

Glasses fitted with lenses that refract light rays to allow the image to form on the retina.

44
Q

Why are you short sighted?

A

Short-sightedness happens when rays of light focus in front of the retina.

45
Q

Why are you long sighted?

A

Long-sightedness happens when rays of light focus behind the retina

46
Q

What is colour blindness caused by?

A

It is caused by defects in the cone cells. Cone cells (detect light colour) and rod cells (detect light intensity) are photoreceptors (light-sensitive cells in the retina).

47
Q

What is a cataract on the eye?

A

Cataracts are caused by a build-up of protein on the lens, that make the pupil cloudy.

48
Q

Whats the difference between embryonic and adult stem cells?

A

Embryonic stem cells are extracted from an early-stage embryo which can then differentiate into different organ tissues.
Adult stem cells only produce the type of specialised cells that are in the tissue around them.

49
Q

What happens when a concious reaction is taking place?

A

Stimulus detected by a receptor cell.

Sensory neurone transmits impulse from receptor to spinal cord

To the brain to be processed and back down the spinal cord

Motor neurone transmits impulse to the effectors

50
Q

How are nerve cells specialised?

A

Long, so impulses travel quick

Insulating sheath to speed up the tranmission of the impulse, stopping signal losing energy as it insulates the impulse

Myelin sheath gaps speed up neurotransmission as impulse ‘jumps’ along the cell

51
Q

What do synapses do?

A

Release neurotransmitters from axon terminal
Slows down neurotransmission
Needed so impulses only flow in one direction
Many impulses at once doesn’t lose strength

52
Q

How do PET scans work?

A

Inject with radioactive glucose (Active cells take in more glucose)

Radioactive glucose creates gamma rays which scanner detects

53
Q

How do CT scans work?

A

The detector measures x-ray absorption and creates an image.

The denser the material = the more x-rays absorbed.

Possible tumours appear as white blotches on the scan

54
Q

WHat happens during interphase?

A

DNA is replicated and cell produces extra sub cellular cell parts (mitochondria, ribosomes. etc)
Copies of the chromosomes stay attached to eachother like X’s

(Interphase is NOT a stage of mitosis, its the preparation)

55
Q

How can plant growth can be monitored ?

A

By measuring :
Increase in mass
Increase in volume
Increase in height
Increase in girth

56
Q

Whats at the end of every plant root and shoot?

A

A group of MERISTEM cells.

-These divide by mitosis and the cells can elongate and differentiate

57
Q

What are some leaf cell adaptions?

A

Epidermis cells (waxy layer) to stop leaves losing too much water.
Its transparent to allow light to pass through palisade cells.

58
Q

What do palisade cells contain?

A

Alot of chloroplasts for photosynthesis.

59
Q

Where do chloroplasys move in dim and bright light?

A

Dim : closer to surface
Birght : move down to prevent damage

60
Q

What is on the bottom of the leaf? they do what?

A

Stomata cells which are open and closed by guard cells to control gas exchange

61
Q

What are the 2 types of stem cells?

A

Embryonic
- Can differentiate into all types of cells
- Taken from embryos

Adult stem cells
- Can only differentiate into certain type of cells eg. blood cells
- Taken from bone marrow of adults

62
Q

What are advantages of embryonic stem cells?

A

Create many embyros in lab or donated embyros
Painless techniques
Treat many diseases
Become any type of cell

63
Q

disadvantages of embryonic stem cell?

A

Destroys embyros
unreliable
cancer
Rights for embyros - cannot consent

64
Q

Advanategs of adult stem cells

A

no ethical issues
Reliable techniques
Can treat some diseases
Quick recovery
Procedure is relatively safe

65
Q

Disadvatges of adult stem cells

A

Risk of infection
procedure can be painful
Can only treat a feew diseases

66
Q

What is meiosis?

A

A type of cell division that reduces the number of chromosomes in the parent cell by half and produces FOUR GAMETE CELLS

67
Q

dIFFERENCE BETWEEN MITOSIS AND MEIOSIS

A

MeiOsis produces 4 cells
Mitosis produces 2 cells

MeiOsis happens only in reprod organs
Mitosis happens everywhere

MeiOsis is to produce gametes
Mitosis is for growth and repair

Cells produced in meiOsis are genetically different
While mitosis ones are identical

In meiOsis, the cell divides twice whereas in miTosis it divides once

In meiOsis, the cells produced have half the n.o of chromosomes
In mitosis the cells produced have the full number of chromosomes

68
Q

Advantage and disadvanatge of stem cells

A

Offers way to treat diseases caused by damaged cells eg. t1 diabetes

BUT

can cause cancer if continuous division
Can be attacked by immune and rejected

69
Q

What happens when a CONSCIOUS reaction is taking place? Not reflex

A

The stimulus is detected by a receptor.

The sensory neurone carries the signal from receptor to spinal cord.

TO THE BRAIN TO BE PROCESSED BACK DOWN SPINAL CORD

The motor neurone transmits impulses to effecyors. (muscles or glands)

An effector brings about an action in response.

70
Q

wHAT is the peripheral nervous system made up of? (PNS)

A

Neurones/nerves

71
Q

How are nerve cells specialised?

A

Nerve cells are long, so electrical impulses travel quickly

They have an insulating sheath to speed up transmission of the elctrical impulse and stops signal losing energy as it insulates the im pulse

Myelin sheath gaps speed up neurotransmission as the impulse ‘jumps’ along the cell

72
Q

What is a synapse?

A

A gap between nerve cells.
(20 Nm wide) 0.00002mm

73
Q

What are the steps of meiosis?

A
  1. each chromosome replicates and attach forming an X
  2. Pairs split into two new cells (1st cycle of division)
  3. Copies now split the X split into 2 (2nd cell division) (HAPLOID)
74
Q

Why is meiosis important?

A

it allows sexual reproduction to occur resulting in natural variation within the same species

biology (9 decks)

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