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Biology Nat5 > Unit 2 Biology > Flashcards

Unit 2 Biology Flashcards

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1
Q

How many chromosomes do average human body cells contain?

A

46 chromosomes which are arranged in 23 pairs.

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2
Q

Where do the two sets of chromosomes come from?

A

One from the mother and one from the father

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3
Q

What is the term used to describe a cell containing two copies of each chromosome?

A

A diploid cell

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4
Q

What is the number of chromosomes a cell contains called?

A

It’s chromosome complement

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5
Q

What is the make up of a chromosome?

A

A chromosome is made of two chromatids joined at the centromere.

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6
Q

Explain unicellular and multicellular division

A

When unicellular organisms divide, they form a complete copy of themselves.

When multicellular organisms divide they produce more cells for growth and repair.

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7
Q

What is Mitosis? (Definition, key points and process)

A

The process of a diploid cell dividing is known as mitosis.
It is controlled by the nucleus.

During mitosis, two identical daughter cells are produced which contain the same number of chromosomes as the parent cell.

This is important so that no information is lost and the cell can carry out the same functions at the parent cell.

Check your booklet to see the correct diagram

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8
Q

Draw and label an accurate diagram for mitosis

A

Page 3, unit two

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9
Q

What do stem cells in animals do?

A

They divide and have the potential to become different types of cell. Stem cells are involved in growth and repair.

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10
Q

Remember the diagram in page four of unit two

A

Stem cell
self-renewal differentiation

Stem cell Specialised cell

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11
Q

Draw and state the structure and function (and any other details) of the following specialised cells:
Nerve cell- Neuron
Red blood cell
Sperm cell
Root hair cell
Leaf cell
Xylem vessel cell

A

To check the drawings go to page four of unit 2

Nerve cell- has connections at each end to link with other nerve cells. Can conduct electrical impulses

Red blood cell- Has no nucleus so it can carry more oxygen. It’s BICONCAVE shape=large surface area for rapid absorption of oxygen. Its small and flexible to fit capillaries.

Sperm cell- To fertilise the egg, it has a tail to swim.

Root hair cell- Has a large surface area that allows for more water absorption. Has no chloroplasts as it is not exposed to light.

Leaf cell- had many chloroplasts to carry out photosynthesis

Xylem vessel cell- Is a continuous tube of dead cells for the transport of water and minerals. Rings of lignin are there to provide support.

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12
Q

How can you organise multicellular organisms?

A

Cell
The basic units of life

Tissue
Groups of cells work together to form tissues

Organ
Groups of tissues work together to form organs

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13
Q

In multicellular organisms do cells work independently?

A

No they do not, they work together to help the organism survive.
This means that internal communication is needed to Co-ordinate the action of all the different body tissues.

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14
Q

What are the two main methods of communication in the body?

A

Electrical impulses that travel through neurones

Hormones that are carried in the bloodsteam

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15
Q

What are hormones?

A

Chemical messengers

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16
Q

What is the nervous system responsible for?

A

Collating the information available from the senses and Co-ordinating the response

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17
Q

What is CNS short for and what does it contain?

A

The central nervous system also called the CNS contains:
The brain
The spinal cord

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18
Q

Draw and label a human with their spinal cord, brain and neurones depicted

A

Check page 6 for a rough diagram

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19
Q

What are neurones?

A

Neurones are long thing cells through which nerve impulses travel in one direction only

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20
Q

What are the three types of neurones?

A

Sensory neurones, inter neurones and motor neurones.

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21
Q

What do sensory neurones do?

A

The sensory neurone carries out messages from the senses to the central nervous system.

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22
Q

What do inter neurones do?

A

Inter neurones carry messages within the central nervous system.

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23
Q

What do motor neurones do?

A

Motor neurones carry messages from the central nervous system to the muscles.

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24
Q

Draw the stimuli, receptors, effectors and responses diagram found at the top of page seven

A

Stimulus > Receptor > Sensory neurone > CNS > Motor neurone > effector > Response

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25
Q

Give an example of a stimuli, receptor, effector and response

A

Check page seven

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26
Q

State the three parts of the brain you know using your national five knowledge

A

The Cerebrum which controls conscious thoughts, memory and personality.

The Cerebellum which controls muscle coordination and balance.

The Medulla which controls breathing and heart rate.

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27
Q

Explain the location of the parts of the brain

A

Check page seven of the unit two booklet

28
Q

What is the name for the place where two neurones meet?

A

The synapse

29
Q

Describe the synapse, then draw and label the diagram

A

When a nerve impulse arrives at the end of the one neurone it causes a release of chemicals (neurotransmitters) from synaptic vessels.

The chemicals diffuse across the synaptic cleft and bind with receptors on the next neurone, triggering another impulse.

Check page seven for the diagram

30
Q

What is a reflex arc?

A

The nerve pathway which follows a reflex action.

Rapid reflex action provides protection against possible harmful stimuli e.g. heat and pain. A receptor detects a stimulus (stimuli) and sends an impulse through a sensory neurone.

The sensory neurone passes the information onto a relay neurone which is within the spinal cord of the CNS.

The impulse is passed onto a motor nerve which is connected to an effector e.g. rapid of contraction of muscles or slow release of hormones from a gland.

31
Q

Give examples or reflex’s and their reflex arcs

A

Check page 8

32
Q

What produces hormones?

A

Endocrine glands

33
Q

Where are hormones released? What do hormones do?

A

Into the blood and they bring about changes in the body.

34
Q

Why do target cells have complementary receptor proteins?

A

So that their specific hormones only affect their tissue. (If this is is confusing look at page 8)

35
Q

Are the effects of hormones on their target tissues long lasting ?

A

Yes they can be and examples are in page eight.

36
Q

Draw a hormonal control diagram

A

Page eight

37
Q

Why must blood glucose levels in your body remain constant?

A

Because changes in blood glucose levels can affect osmosis in body cells.

38
Q

What happens to your blood glucose levels after a meal? How do they revert to normal?

A

They increase and the body must return the glucose levels to normal.

The pancreas detects the change and sends insulin to the liver. The liver then turns excess glucose into glycogen.

39
Q

What is glycogen?

A

A storage carbohydrate

40
Q

What happens to your blood glucose levels overnight or during periods of fasting?
How does the body revert to the normal blood glucose levels?

A

Blood glucose can dehydrate overnight or during periods of fasting.
The body must return the glucose levels to normal.

The pancreas detects the change and sends a different hormone called glucagon to the liver. The liver then converts glycogen stored to glucose.

41
Q

What is glucagon?

A

Glucagon is a hormone that your pancreas makes to help regulate your blood glucose levels.

42
Q

Please view the diagram in the middle of page nine

A

:)

43
Q

What happens in dangerous situations?

A

Adrenal glands release adrenaline which quickly converts glycogen to glucose for an energy source for the body.

44
Q

What is diabetes?

A

Being unable to control the levels of sugar in your blood system.

The failure in the communication pathway which regulates blood sugar levels.

45
Q

What are the differences in type one and two diabetes?

A

Type one
Is early, rapid onset,
no insulin produced,
requires injections

Type two
Overweight, elderly
Resistance to insulin
Healthy balance lifestyle

46
Q

What has two sets of chromosomes- one set from the mother and one from the father. (Diploid cells)

A

All body cells

47
Q

What are Haploid cells?

A

Sex cells (gamete cells) have only one set of chromosomes these are known as haploid cells

Human gamete cells have 23 chromosomes

48
Q

What happens during fertilisation?

A

The full chromosome complement of a cell is restored.

The nucleus of the male gamete fuses with the nucleus of the female gamete to form a zygote.

The zygote is genetically unique and increases variation within a species.

49
Q

What are the parts of the male reproductive system?

A

The sperm duct, Urethra, Testes and Penis as shown on page 11

50
Q

What are the parts of the female reproductive system?

A

The oviducts, ovaries, uterus and Vagina

As seen on page 11

51
Q

What is the name of the male gamete and where is it produced? What is it’s structure?

A

The sperm is produce in the testes. Head with nucleus and flagellum (tail) for swimming to the egg.

52
Q

What is the female gamete and where is it produced? What is the structure of a he female gamete?

A

The ovum is produced in the ovaries. The ovum has a cytoplasm and a nucleus.

53
Q

Where does fertilisation in animals occur inside the female?

A

The oviduct

54
Q

Draw and label a plants reproductive system

A

Page 12

55
Q

What is the male gamete in plants and where is it produced?

A

The pollen is produced in the anther

56
Q

Where is the female gamete in the plant and what’s it called?

A

The ovule is produced in the ovary

57
Q

What does the ovule become after fertilisation?

A

The ovule becomes a seed and the ovary becomes the fruit.

58
Q

What must happen for plant fertilisation to occur?

A

Pollen needs to travel from the stigma to the ovary to fertilise the ovule. This is done through the pollen tube, which the pollen grain grows through the style.

The male nucleus travels down the pollen tube and fuses with the female gamete .

59
Q

List three ways that plants attract insects for pollination

A

Nectar
Colour
Smell

60
Q

How can plants be pollinated?

A

By self pollination, pollination from another plant by wind or insect.

61
Q

State different methods of seed dispersal

A

Wind, animals, explosion,

Possibly gravity and water

62
Q

Why do the stamen and stigma hang outside the flower?

A

The stamen hangs out the flower to release pollen into the wind and the stigma hangs out to catch the pollen.

63
Q

Why is the stigma feathery?

A

This gives a larger surface area and so makes it more efficient at catching pollen.

64
Q

What causes variation in a species?

A

Variation is partly due to the genes we inherit.

65
Q

What are discrete variations?

A

Discrete variations are discrete groups of individuals with no values in-between (E.g individual can either roll their tongue or cannot) definite

Biology Nat5 (8 decks)

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