cell biology (p1) Flashcards
(71 cards)
1
Q
eukaryotic cell
A
plant and animal cells (has nucleus)
2
Q
prokaryotic cell
A
bacterial cells (no nucleus)
3
Q
role of nucleus
A
contains DNA
4
Q
role of ribosomes in a cell
A
makes proteins
5
Q
role of cytoplasm
A
where chemical reactions happen
6
Q
role of mitochondria
A
where aerobic respiration occurs
7
Q
role of vacuole
A
stores sap
8
Q
role of chloroplasts
A
where photosynthesis happens
9
Q
role of cell membrane
A
controls what enters and exits the cell
10
Q
role of cell wall
A
strengthens the cell
11
Q
function of sperm cells
A
reproduction
12
Q
function of muscle cells
A
movement
13
Q
function of nerve cells
A
carrying messages quickly
14
Q
function of root hair cells
A
absorption of water and mineral ions
15
Q
function of phloem cells
A
transporting cell sap
16
Q
function of xylem cells
A
transporting water and dissolved minerals
17
Q
cell differentiation
A
when a cell becomes specialised
18
Q
chromosomes in a human body cell
A
23 pairs (46 in total)
19
Q
cell cycle
A
process when a cell grows, then divides to form two identical cells
20
Q
3 phases of cell cycle
A
1) growth 2) mitosis 3) division
21
Q
stem cell
A
unspecialised cell or organism
22
Q
embryonic stem cells
A
Unspecialised cells in embryos which can develop into any type of cell
23
Q
adult/mature stem cells
A
Stem cells found in adults.They cannot differentiate into any type of cell
24
Q
main function of mature stem cells in the body
A
repairing and replacing cells
25
meristem cells
unspecialised cells that can differentiate into any type of plant cell
26
diffusion
the net movement of particles from an area of high concentration to an area of low concentration
27
what is the inside of the small intestine covered in?
Villi
28
osmosis
the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
29
active transport
when substances move from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration
30
what type of cell is a bacterial cell
prokaryotic
31
what is smaller: plant cell or bacterial cell
bacterial
32
how can u identify a prokaryotic cell
has no nucleus
33
how can u identify a eukaryotic cell
has nucleus
34
how are sperm cells specialized for reproduction
long tail for movement
contains lots of mitochondria for respiration to generate energy for movement
35
How are muscle cells specialised for contraction?
Contain lots of mitochondria for respiration to generate energy for contraction
36
How are nerve cells specialised for rapid signalling?
1) Long cell to carry information over long distances
2) branches so that it can communicate with many other cells
37
How are root hair cells specialised for absorption?
large surface area for absorption
38
How are xylem cells specialised for the transportation of water?
Dead cells form long, hollow tubes up which water can travel with little resistance
39
How are phloem cells adapted for the transportation of food substances
Living cells with few organelles form long tubes up which cell sap / food can travel with little resistance
40
when do animal cells usually differentiate
at an early stage
41
When do plant cells usually differentiate?
any time through their life
42
How do electron microscopes compare to light microscopes?
Electron microscopes: higher magnification, higher resolving power, more expensive
43
What equation links size of image, size of object, and magnification?
magnification = size of image ÷ size of real object
44
How did electron microscopes affect biologists?
they allowed biologists to see and understand many more structures in cells
45
How many chromosomes are in a human body cell?
23 pairs (46 in total)
46
Why do body cells normally have two copies of each chromosome?
One from the mother, one from the father.
47
What do genes control?
The development of different characteristics.
48
What is the cell cycle?
The process in which a cell grows, then divides to form two identical cells
49
What are the three phases of the cell cycle?
1) Growth
2) Mitosis
3) Division
50
What happens in the growth phase of the cell cycle?
the DNA replicates to form two copies of each chromosome, and the number of ribosomes and mitochondria increases
51
What happens in the mitosis phase of the cell cycle?
one set of chromosomes is pulled to each end of the cell and the nucleus divides
52
What happens in the cell division phase of the cell cycle?
the cytoplasm and cell membranes divide to form two identical cells
53
What is a stem cell?
an unspecialised cell of an organism
54
What are embryonic stem cells?
Unspecialised cells in embryos which can develop into any type of cell
55
What are adult/mature stem cells?
Stem cells found in adults.They cannot differentiate into any type of cell
56
What is the main function of mature stem cells in the body?
Repairing and replacing cells.
57
What are meristem cells?
unspecialised cells that can differentiate into any type of plant cell
58
Where in plants is meristem tissue found?
The tips of shoots and in the roots.
59
What is therapeutic cloning?
A process which produces an embryo with the same genes as the patient. This means that the stem cells produced by the embryo are not rejected by the patient's body during medical treatment.
60
Why are some people against stem cell research?
They have ethical or religious objections
61
How can we use stem cells from meristems?
Cloning plants quickly and economically, so that we can:
1) Protect rare species from extinction.
2) Clone plants with desired features for farmers, e.g. disease resistance.
62
What substances move in and out of human cells by diffusion?
oxygen and carbon dioxide in gas exchange, and urea from cells
63
How are surfaces in organisms adapted for efficient exchange of substances?
1) Thin membranes
2) Large surface area
3) lots of blood vessels in animals
4) good ventilation (lots of gases moving past)
64
What is the inside of the small intestine covered in?
Villi (which increase surface area)
65
How is the structure of villi related to their function?
1) They increase the surface area of the small intestine.
2) They are thin to reduce the distance across which diffusion occurs
3) They have a good blood supply for the uptake of substances.
66
How is the underneath of a leaf adapted for diffusion of gases?
1) Covered in stomata
2) large surface area
3) Air spaces between cells inside leaf increase ventilation
67
What is the gas exchange surface in fish?
The gills.
68
How is the structure of gills adapted for gas exchange?
1) large surface area for gas exchange
2) thin to reduce the distance across which diffusion occurs
3) good blood supply
4) A large concentration gradient is maintained between the water and blood, so rate of diffusion into blood is maximised
69
What is osmosis?
the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
70
What is active transport
when substances move from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration
71
What are examples of active transport?
1) mineral ions are absorbed into plant root hairs from very dilute solutions in the soil
2) sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration
