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Year 9 Science > Cell biology > Flashcards

Cell biology Flashcards

1
Q

What type of cell division happens to produce new BODY cells?

A

Mitosis

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2
Q

What type of cell division in sexually reproducing organisms reduces the number of chromosomes in gametes (the sex cells, or egg and sperm)?

A

Meiosis

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3
Q

What reasons are there as to why the survival rates for all cancers have increased?

A

improved treatment / drugs
earlier diagnosis
more cancer screening
improved patient knowledge (of risk factors)
allow improved patient diet / lifestyle

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4
Q

Some parts of the human body have adaptations to reduce the entry of live pathogens.

Explain how the trachea is adapted to reduce the entry of live pathogens.

A

..has MUCUS to trap pathogens

..has CILIA to move mucus out of trachea

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5
Q

On the mosquito exam question, it asks about ‘control variables’. Name some!

A
  • number of mosquitoes in each container
  • length of time socks worn
  • dampness of socks
  • same type of socks
  • size of container
  • time
  • temperature
  • species of mosquito
  • age of mosquito
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6
Q

If there are 2 out of 22, what is that as a percentage to 2 decimal places?

A

9.09

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7
Q

Many types of cell can divide to form new cells.

Some cells in human skin can divide to make new skin cells.

Why do human skin cells need to divide?

A

For REPAIR and GROWTH or to replace cells.

Cell division is necessary for GROWTH and REPAIR!

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8
Q

Human stem cells can develop into many different types of human cell.

Human stem cells may come from:

a) embryos
b) hair
c) nerve cells

A

a) embryos

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9
Q

Use the correct answer from the box to complete the sentence.

Human stem cells can be used to treat:

a) cystic fibrosis
b) paralysis
c) polydactyly

A

b) paralysis

Paralysis could be treated with human stem cells!

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10
Q

The blood going to the stomach has a high concentration of oxygen.

The cells lining the stomach have a low concentration of oxygen.

Complete the following sentence.

Oxygen moves from the blood to the cells lining the stomach by the process of ________

A

diffusion

DIFFUSION!!!!

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11
Q

In an image of the lungs, what are the little ‘air sac’ structures that appear like branches on a tree?

A

alveoli

alveolus

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12
Q

Oxygen moves from the lungs into the blood through the walls of the __________________________ .

A

capillaries

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13
Q

Inside the lungs, oxygen is absorbed from the air into the blood.

Give two adaptations of the lungs that help the rapid absorption of oxygen into the blood.

A
  • (have many) alveoli
  • large surface / area
  • thin (exchange) surface or short diffusion pathway
  • good blood supply / many capillaries
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14
Q

The leaves of plants have stomata.

What is the function of the stomata?

A

carbon dioxide in

or

oxygen out

or

CONTROL water loss.

(‘CONTROL’ is a key idea here Tommy that the examiners want to see.)

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15
Q

How do CLOSED stomata look different in a diagram to open stomata?

A

The closed ones look like an eye that’s closed, whereas the open ones look like an eye that’s open!

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16
Q

What happens to plants if not watered?

A

They wilt or droop

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17
Q

Fertilised eggs get inserted…

A

..into the mothers UTERUS or WOMB

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18
Q

The villi absorb the products of digestion by…

A

diffusion

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19
Q

in which part of the digestive system, are most villi found?

A

Small intestine

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20
Q

Why is it helpful to have lots of villi?

A

larger surface area , absorb more food

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21
Q

What sex chromosomes will be found in the body cells of a man, and a woman?

A

Man : XY or YX or Y and X
Woman : XX or X and X

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22
Q

A man and a woman decide to have a child. What is the chance that the child will be a boy?

A

50 % or 50/50

23
Q

Name one gas that will diffuse into a plant leaf on a sunny day

24
Q

SOME sperm cells have…

A

an x chromosome

25
Name 3 advantages of using embryo stem cells, and bone marrow stem cells
EMBRYO : each cell divides every 30 minutes, can develop into most other types of cell, low chance of rejection by the patient’s immune system Bone marrow : cheaper / only costs £1000, can collect many (stem) cells, adults give permission for their own bone marrow to be collected, safe
26
State if the concentration of oxygen and carbon dioxide would be higher or lower when inhaled and exhaled
Oxygen : Inhaled; higher, exhaled ; lower Carbon dioxide: inhaled; lower, exhaled ; higher
27
A person who has cystic fibrosis has ... copies of the cystic fibrosis allele
two
28
The cystic fibrosis allele is..
recessive
29
Which part of the cell is affected by cystic fibrosis?
cell membarane
30
State 3 ways in which the villus is adapted to help the absorption of soluble foods
its outer surface is one cell thick, it has a large surface area, it has good blood supply
31
Name the process by which soluble food enters the blood.
diffusion
32
how does having lots of root hair cells help plant ?
larger surface area to absorb more water / ions
33
Calculate the average diameter of these cells: cell 1: 63 micrometres ,cell 2: 78 micrometres, cell 3: 69 micrometres
70
34
Name the process by which oxygen moves across the wall of the alveolus.
diffusion
35
Each lung contains about 350 million alveoli. How does this help gaseous exchange?
large surface or large area
36
What is the main job of a leaf mesophyll cell?
has chlorophyll/chloroplasts to absorb light/produce food
37
What type of pathogen causes malaria
Protist
38
What type of pathogen causes measles
Vitus
39
When chloroplasts are destroyed, how does it affect the plant growth
Less chlorophyll present = less light absorbed = reduced photosynthesis
40
What is the function of stomata
Carbon dioxide in Water out Control water loss
41
What is the reason for having a 50% chance of having a girl
Half the sperm contain an X chromosome
42
Why do they only use one embryo in ivf
Fewer twins
43
In what direction does osmosis flow?
High water to low water (in order to dilute it!)
44
Plants need nitrate ions in order to make proteins. A plant is growing in soil flooded with water. Explain why the plant cannot absorb enough nitrate ions.
(nitrate) ions are absorbed by active transport 1 (active transport) is the movement of ions against the concentration gradient allow (active transport) is the movement of ions from a dilute to a more concentrated solution 1 (active transport) requires energy from respiration 1 (respiration) requires oxygen 1 no / little oxygen / air in water-logged soil 1
45
Drug manufacturers are spending less on research into new antibiotics. One reason why is because new antibiotics are rarely prescribed. Some people think that governments should pay drug manufacturers to develop new antibiotics. Suggest why.
antibiotics are being developed at a slower rate than emergence of new resistant strains 1 resistant strains mean we cannot treat (common) infections 1 reduce (future) cost of antibiotic resistant infections 1
46
The diagram below shows how a nerve impulse passing along a relay neurone causes an impulse to be sent along another type of neurone, neurone X. ( NEURONE X LOOKS LIKE A LONG CRAB CLAW WITH A SURRATED EDGE!!) What type of neurone is neurone X?
Motor
47
Describe how information passes from the relay neurone to neurone X.
release of chemical (from relay neurone) allow ecf for ‘motor’ neurone from (a) allow release of neurotransmitter / named example 1 chemical crosses gap / junction / synapse allow diffuses across allow chemical moves to X
48
Scientists investigated the effect of two toxins on the way in which information passes across synapses. The table below shows the results. Curare Decreases the effect of the chemical on neurone X Strychnine Increases the amount of the chemical made in the relay neurone Describe the effect of each of the toxins on the response by muscles.
(curare) decrease / no contraction accept (muscle) relaxes 1 (strychnine) increase / more contraction if no other mark awarded allow 1 mark for (curare) decrease / no response and (strychnine) increase / more response 1
49
What is a dominant allele?
llele expressed even when other allele present or expressed if just one copy of allele is present or expressed if heterozygous
50
homozygous and heterozygous
Homozygous means you've inherited the same alleles of a gene from each of your parents. In contrast, heterozygous means you've inherited different alleles of a gene from each of your parents
51
how to calculate order of magnitude
if you have 2 numbrs to compare alway`s divide the biger number by the smaller number
52
a small animal cell has a lenght of 10 um. a large plant cell has a lenght of 100um. calculate the order of magnitude
100/10=10 so large plant cell is an order of magnitude bigger
53

Year 9 Science (3 decks)

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