cell biology & organisation Flashcards
(80 cards)
1
Q
nucleus
A
controls activities of the cells, contains genetic material
2
Q
cytoplasm
A
most chemical reactions take place
3
Q
cell membrane
A
controls what goes in and out of the cell
4
Q
mitochondria
A
where aerobic respiration takes place
5
Q
ribosomes
A
where proteins are synthesised (made)
6
Q
synthesised means..
A
made
7
Q
animal cell contains=
A
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
8
Q
plant cell has the same as animal cell +
A
cell wall, vacuole, chloroplasts(some)
9
Q
cell wall is made of
A
cellulose
10
Q
cell wall
A
strengthens the cell
11
Q
permanent vacuole is filled with
A
cell sap
12
Q
vacuole
A
supports the plant
13
Q
chloroplasts
A
absorb light to make food by photosynthesis
14
Q
root cell
A
does not contain chloroplasts
15
Q
why does the root cell not contain chloroplasts?
A
it does not receive any light
16
Q
bacterial cells
A
prokaryotic
17
Q
plant, animal + fungal cells
A
eukaryotic
18
Q
prokaryotic cell
A
does not contain mitochondria or chloroplasts
19
Q
plasmids
A
allow bacterial cells to move genes from one cell to another
20
Q
flagella
A
tail-like to help some bacteria move
21
Q
why are plasmids useful for scientists?
A
allow genes to be inserted into bacteria in genetic engineering
22
Q
magnification=
A
size of image
—————————
size of real object
23
Q
chromosomes
A
made of DNA
24
Q
each chromosome=
A
carries hundreds of thousands of genes
25
how many pairs of chromosomes do humans have?
23 pairs
26
stem cells are:
undifferentiated cells which can divide to make different types of cells
27
where are stem cells found?
human embryos
28
what are the uses of stem cells?
treating conditions where cell is damaged or not working properly (diabetes)
29
2 concerns of stem cells are:
- may be risks (infection)
| - ethical or religious objections
30
why is it important that the chromosomes are copied before mitosis occurs?
to increase the number of sub-cellular structures (ribosomes & mitochondria)
31
diffusion is..
movement in and out of cell across the membrane
32
diffusion moment of particles:
area of higher concentration to an area of lower concentration
33
examples of diffusion=
gas exchange- oxygen and carbon dioxide in the lungs, gills and plant leaves
34
factors affection diffusion=
- concentration gradient (difference in concentration)
- temperature
- surface area of membrane
35
osmosis is..
the diffusion of water from a dilute solution to a concentrated solution through a particularly permeable membrane
36
water moves across cell membrane by..
osmosis
37
active transport..
moves substance against a concentration gradient
38
active transport concentration =
low to high
39
active transport requires
energy from respiraton
40
specialised cells
become more efficient at their job but lose the ability to do other jobs
41
how is a specialised cell developed?
it differentiates
42
what happens when a cell differentiates:
- change shape
| - different sub-cellular structures develop (let it carry out specific function)
43
examples of specialised animal cells=
sperm, muscle, nerve
44
examples of specialised plant cells=
root hair, xylem, phloem
45
tissue=
group of cells with similar structure & function which work together to do a job
46
example of tissue:
muscle tissue contracts to produce movement
47
organs=
group of different tissues which work together to perform a job
48
example of organ=
stomach
49
why do cells differentiate?
to turn into a specialised cell so it can carry out a specific function
50
why does sperm cell contain a lot of mitochondria?
to provide energy for the journey
51
enzymes (biological catalysts)...
speed up a chemical reaction
52
properties of enzymes=
- large proteins
- space within molecule (active site)
- each enzyme catalysed a specific reaction
- work best at a specific temperature
53
what theory is used to explain how enzymes work?
‘lock and key theory’
54
denaturing=
when high temperatures and extreme of pH make enzymes change shape
55
after the enzyme has been denatured...
it can’t work as substrate can’t fit into active site
56
where are digestive enzymes produced?
in glands + lining of gut (by specialised cells)
57
what is amylase?
carbohydrase that breaks down starch into sugar
58
where is amylase prouduces?
salivary glands + pancreas
59
protease...
breaks down proteins into amino acids
60
where is protease produced?
in the stomach, pancreas + small intestines
61
lipase..
breaks down lipids (fats) into fatty acids and glycerol
62
where is lipase produced?
in the pancreas and small intestine
63
what is bile?
an alkaline which neutralises hydrochloric acid from the stomach
64
where is bile made and stored?
```
made= liver
stored= gall bladder
```
65
blood is made of a liquid called...
plasma
66
blood is a..
tissue
67
plasma components..
- red blood cells
- white blood cells
- platelets
68
red blood cells..
- contain haemoglobin
- does not contain a nucleus
- very small (fit through capillaries)
- biconcave discs (large surface area)
69
haemoglobin
transport oxygen in the blood
70
white blood cells:
- help protect the body against infection
| - can change shape (squeeze out of blood vessels)
71
platelets
fragments of cells, collect at wounds and trigger blood clotting
72
3 type of blood vessels:
- arteries
- veins
- capillaries
73
arteries...
- take blood from your heart to your organs
| - have thick walls made from muscle and elastic fibres
74
veins...
- take blood from your organs to your heart
| - thinner walls and valves to prevent backflow
75
capillaries..
- allow substances needed by the cells to pass out of the blood
- allow substances produced but the cells to pass into the blood
- narrow, thin walled blood vessels
76
the heart:
pumps blood around the body in a double circulatory system
77
4 chambers:
- left + right atria (receive blood from veins)
| - left + right ventricle (pump out into arteries)
78
artificial pace makers:
electrical devices used to correct irregularities in the heart rate
79
gaseous exchange pathway:
1) trachea
2) bronchi
3) bronchioles
4) alveoli
80
alveoli:
- large, moist surface area
- very rich blood supply
- close to blood capillaries (short distance to diffuse)
