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Biology❌ > SB2 > Flashcards

SB2 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is mitosis?

A

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus.

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2
Q

What are the main stages of the cell cycle?

A
  1. Interphase
  2. Prophase
  3. Metaphase
  4. Anaphase
  5. Telophase
  6. Cytokinesis
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3
Q

What’s the prophase?

A

The chromosomes condense, getting shorter and fatter. The membrane around the nucleus breaks down and the chromosomes lie free in the cytoplasm.

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4
Q

What’s the metaphase?

A

The chromosomes line up at the centre of the cell.

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5
Q

What’s the anaphase?

A

Cell fibres pull the chromosomes apart.

The two arms of each chromosomes go to opposite ends of the cell.

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6
Q

What’s the telophase?

A

Membranes form around each of the sets of chromosomes.

These become the nuclei of the two new cells - the nucleus has divided.

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7
Q

What happens in the cytokinesis process?

A

Before the telophase ends, the cytoplasm and cell membrane divide to form two separate cells.

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8
Q

What’s the interphase?

A

In a cell that’s not dividing, the DNA is all spread out in long strings. Before it divides, the cell has to grow and to increase the amount of subcellular structures such as mitochondria and ribosomes.

It then duplicates its DNA - so there’s one copy for each new cell. The DNA is copied and forms X shaped chromosomes. Each ‘arm’ of the chromosomes is an exact duplicate of the other.

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9
Q

What has been produced at the end of mitosis?

A

The cell has produced two new daughter cells.

Each daughter cell contains exactly the same sets of chromosomes in its nucleus as the other daughter cell - they’re genetically identical diploid cells.

They’re also genetically identical to the parent cell.

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10
Q

What is growth?

A

An increase in size or mass.

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11
Q

What are the processes that cause plants and animals to grow and develop?

A
  1. Cell differentiation
  2. Cell division
  3. Cell elongation
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12
Q

What is cell differentiation?

A

The process by which a cell changes to become specialised for its job. Having specialised cells allows multicellular organisms to work more efficiently.

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13
Q

What is cell division?

A

Mitosis.

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14
Q

What is cell elongation?

A

This is where a plant cell expands, making the cell bigger and so making the plant grow.

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15
Q

How does animal growth happen?

A

It happens by cell division.

Animals tend to go while they’re young, and then they reach full growth and stop growing.
When you’re young, cells divide at a fast rate but once you’re an adult most cells divide for repair.

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16
Q

How does plant growth happen?

A

Growth in height is mainly due to cell elongation

Cell division usually just happens in the tips of the roots and shoots.

Plants often grow continuously - they continue to differentiate to develop new parts.

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17
Q

Give an example of uncontrolled cell division

A

Cancer

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18
Q

What controls the rate at which cells divide by mitosis?

A

Controlled by the chemical instructions (genes) in an organisms DNA.

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19
Q

What causes a cell to divide uncontrollably?

A

If there’s a change in one of the genes that controls cell division.

This can result in a mass of abnormal cells called a tumour.
If the tumour invades and destroys surrounding tissue it’s called cancer.

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20
Q

What are percentile charts used for?

A

Used to monitor growth.

They’re used to assess a child growth over time, so that an overall pattern in development can be seen and any problem highlighted (obesity, malnutrition, dwarfism).

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21
Q

What are undifferentiated cells called?

A

Stem cells.

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22
Q

What can stem cells do?

A

Depending on what instructions they’re given, stem cells can divide by mitosis to become new, which then differentiate.

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23
Q

Why are stem cells important?

A

For the growth and development of organisms.

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24
Q

Where are stem cells found?

A

In early human embryos

Adults - bone marrow

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25
Q

What do meristems contain?

A

Plant stem cells

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26
Q

What are found in meristem?

A

In plants, the only cells that divide by mitosis are found in plant tissues called meristems.

27
Q

What do meristems produce?

A

They produce unspecialised cells that are able to divide and form any cell type in the plant.

The unspecialised cells go on to form specialised tissues like xylem and phloem.

28
Q

Explain how Stem cells can be used in medicines?

A
  1. Doctor already use stem cells to cure some disease (sickle cell anaemia).
  2. Scientists have experimented with extracting stem cells from from very early human embryos and growing them. Under certain conditions the stem cells can be stimulated to differentiate into specialised cells.
  3. It might be possible to use stem cells to create specialised cells to replace those which have been damaged by disease or injury. (New cardiac muscles for someone with heart disease).
29
Q

Before scientists can use stem cells for potential new cures lots of research needs to be done.

Name the risks with using stem cells?

A
  1. Tumour development - stem cells can divide very quickly, creating a tumour.
  2. Disease transmission - viruses live inside cells. If donor stem cells are infected with a virus it could pass on to the patient.
  3. Rejection - if the transplanted cells aren’t grown using the patients own stem cells, then their body might recognise the cells as foreign and trigger an immune response to get rid of them.
30
Q

What makes up the central nervous system?

A

The brain and spinal cord.

31
Q

What is the spinal cord?

A

A long column of neurones that run from the base of the brain down the spine.
At several places down the cord, neurones branch off and connect with other parts of the body.

32
Q

What does the spinal cord do?

A

It relays information between the brain and the rest of the body.

33
Q

Name the different parts of the brain

A
  1. Cerebrum
  2. Cerebellum
  3. Medulla oblongata
34
Q

What does the cerebrum do?

A

It’s the largest part of the brain. It’s divide into two halves cal cerebral hemispheres:
The right hemisphere controls muscles on the left side of the body and vice versa.

Different parts are responsible for different things. (Movement, intelligence, vision etc).

35
Q

What does the cerebellum do?

A

Responsible for muscle coordination and balance

36
Q

What does the medulla oblongata do?

A

Controls unconscious activities like breathing and your heart rate.

37
Q

What are scanners used for?

A

To investigate brain function

38
Q

Name some scanners

A
  1. CT

2. PET

39
Q

What does a CT scanner do and show?

A
  1. It uses X-ray to produce an image of the brain.
  2. A CT scan shows the main structures in the brain, but it doesn’t show the functions of them.
  3. However, if a CT scan shows a diseased or damages brain structure and the patient has lost some function, the function of that part of the brain can be worked out.
40
Q

What does a PET scanner do and show?

A
  1. They use radioactive chemicals to show which parts of the brain are active when the person is inside the scanner.
  2. They can be used to to investigate both the structure and the function of the brain in real time.
  3. It can show if areas in the brain are unusually inactive or active, so they are useful for studying disorders that changes the brains activities.
41
Q

what are sensory receptors?

A

Groups of cells that can detect a change in your environment. Different receptors detect different stimuli.

42
Q

Explain how the CNS coordinates a response?

A
  1. Sensory receptors detect a stimuli.
  2. When a stimuli is detected by receptors, the information in converted to a nervous (electrical) impulse and sent along sensory neurones to the CNS.
  3. The CNS coordinates the response and impulses travel through the CNS along relay neurones.
  4. The CNS send information to an effector (muscles or glands) along a motor neurone. The effective then responds accordingly (muscles may contract).
  5. The time it takes you to respond to a stimulus is called your reaction time.
43
Q

What do neurones do?

A

Transmit information rapidly as electrical impulses.

44
Q

Give the structure and function of sensory neurones?

A

One long dendron carries nerve impulses from the receptor cells to the cell body, which is located in the middle of the neurone.

One short axon carries nerve impulses form the cell body to the CNS.

45
Q

What do dendrons and dendrites do?

A

Carry nerve impulses towards the cell body.

46
Q

What do axons do?

A

Carry nerve impulses away from the cell body.

47
Q

Give the structure and function of motor neurones?

A

Many short dendrites carry nerve impulses from the CNS to the cell body.

One long axon carries nerve impulses from the cell body to effector cells.

48
Q

Give the structure and function of relay neurones?

A

Many short dendrites carry nerve impulses from sensory neurones to the cell body.

An axon carries nerve impulses from the cell body to motor neurones.

49
Q

What are synapses?

A

The connection between two neurones

50
Q

Explain what happens in synapses

A

The nerve signal is transferred by chemicals called neurotransmitters, which diffuse (move) across the gap.

The neurotransmitters then set off a new electrical signal in the next neurone.

The transmission of a nervous impulse is very fast ,but it is slowed down a bit at the synapse because the diffusion of neurotransmitters across the gap take time.

51
Q

What are reflexes?

A

They’re automatic, rapid responses to stimuli

52
Q

What can reflexes help prevent?

A

Injury

53
Q

What is a reflex arc?

A

The passage of information in a reflex (from receptor to effector).

54
Q

How do reflexes protect the eye?

A
  1. Very bright light can damage the eye - so you have a reflex to protect it.
  2. Light receptors in the eye detect very bright light and send a message along a sensory neurone tot the brain.
  3. The message then travels along a relay neurone to a motor neurone, which tells circular muscles in the iris (the coloured part of the eye) to contract, making the pupil smaller.
55
Q

Name the parts of the eye?

A
  1. Cornea
  2. Iris
  3. Lens
  4. Retina
  5. Rods
  6. Cones
  7. Optic nerve
56
Q

What does the cornea do?

A

Refracts (bends) light into the eye.

57
Q

What does the iris do?

A

Controls how much light enters the pupil (the hole in the middle).

58
Q

What does the lens do?

A

Also refracts light, focusing it retina.

59
Q

What does the retina do?

A

It’s the light sensitive part and it’s covered in receptor cells called rods and cones which detect light.

60
Q

What do the rods do?

A

Are more sensitive in dim light but can’t sense colour.

61
Q

What do cones do?

A

Are sensitive to different colours but aren’t so good in dim light.

62
Q

What does the optic nerve do?

A

The information from light is converted into electrical impulses. The optic nerve carries these impulses from the receptors of the brain.

63
Q

What lenses do you need if you’re short or long sighted?

A

Short - convex

Long - concave

Biology❌ (9 decks)

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