Cell Biology Flashcards

Paper 1 - B1

1
Q

What type of organisms are prokaryotic
cells?

A

Bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of organisms have eukaryotic
cells?

A

Plants and animals (& fungi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the function (job) of the nucleus in a cell?

A

To control the cell. Contains DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the function (job) of the cell
membrane?

A

To control what substances can enter or leave the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the function of the mitochondria?

A

To release energy in respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What process takes place at the
ribosomes?

A

Protein synthesis / making proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the role of chloroplasts?

A

Absorb sunlight for photosynthesis. Contains chlorophyll

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is inside the permanent vacuole of a plant cell?

A

Cell sap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name three cell parts (organelles) found in plant cells but not animal cells

A

Cell wall, permanent vacuole, chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name one structure you might find in the cytoplasm of a prokaryotic cell but not in a eukaryotic cell

A

DNA or plasmid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name one structure found in eukaryotic
cells but not prokaryotic cells

A

A nucleus surrounding the genetic material (or accept mitochondria)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which are the smallest, prokaryotic or
eukaryotic cells?

A

Prokaryotic cells are much smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the cell wall made of in plant and algal cells?

A

Cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the adaptations of a sperm cell?

A

Flagella to swim towards the egg, acrosome to digest egg cell membrane, lots of mitochondria to supply energy for swimming, haploid nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the adaptations of a nerve cell?

A

Long axon to transmit nerve impulses,
branched nerve endings/dendrites to
send/receive impulses from other neurones, fatty sheath/insulating layer to speed up nerve impulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the adaptations of a muscle cell?

A

Proteins filaments that slide to cause muscle contraction, lots of mitochondria to release energy, many nuclei because cells have merged to form a stronger structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the adaptations of a root hair cell?

A

Long projection of the cell membrane to increase surface area for water to move in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the adaptations of xylem cells?

A

Dead hollow cells to form a tube for water transport; thickened with lignin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the adaptations of phloem cells?

A

Perforated end walls to act as a sieve for sugar solution to pass through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is cell ‘differentiation’?

A

The process of cells becoming specialised by acquiring different sub-cellular structures to enable it to carry out a certain function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the reasons why cell division is necessary in mature animals?

A

For repair (of tissues) and replacement (of damaged cells), NOT “repair of cells”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How have developments in microscopy allowed us to understand more about subcellular structures such as ribosomes and mitochondria?

A

We have electron microscopes which have a much higher magnification and resolution, so can see finer details inside cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

State two advantages of an electron
microscope over a light microscope.

A

Higher magnification, greater resolving power (resolution)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the formula for magnification?

A

Magnification = size of image / size of real
object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
(Triple only) How do bacteria divide?
By binary fission
26
(Triple only) How often do bacteria divide?
Once every 20 minutes if they have enough nutrients and a suitable temperature
27
(Triple only) Name two types of growth medium for bacteria
Agar gel plate or nutrient broth solution
28
(Triple only) What is the purpose of aseptic technique?
To prepare an uncontaminated culture of microorganisms
29
(Triple only) In aseptic technique, why must petri dishes and culture media be sterilised before use?
To kill any bacteria or other microorganisms that could multiply and contaminate the experiment
30
(Triple only) In aseptic technique, how can inoculating loops be sterilised?
By passing through a Bunsen flame
31
(Triple only) In aseptic technique, why are Petri dishes stored upside down?
To prevent condensation affecting bacterial growth
32
(Triple only) When growing bacteria in a school laboratories, why are cultures generally incubated at temperatures no higher than 25 degrees Celsius?
To prevent the growth of microorganisms that are harmful to humans (which are likely to multiply at temperatures close to body temperature)
33
(Triple only) What formula would you use to calculate the cross-sectional area of a bacterial colony or the clear area around it?
πr²
34
What is found in the nucleus of cells?
Chromosomes made of DNA molecules
35
During the cell cycle, what happens to the genetic material (DNA) before mitosis?
It replicates (doubles)
36
During the cell cycle, aside from the doubling (replication) of the DNA, what else happens within the cell?
The cell grows and increases the number of sub-cellular structures (organelles) e.g. ribosomes, mitochondria
37
What happens to the chromosomes during mitosis?
They are pulled to opposite ends of the cell
38
What happens to the nucleus of a cell at the end of mitosis?
It divides
39
What happens to the cytoplasm and cell membranes at the end of mitosis?
They divide to form two identical cells
40
Why is cell division by mitosis important in multicellular organisms?
For growth and development
41
What is a stem cell?
An undifferentiated cell of an organism, capable of giving rise to many more cells of the same type and from which certain other cells can arise from differentiation.
42
What is the function of stem cells in embryos?
To allow the embryo to grow and produce specialised cells to develop into tissues and organs
43
Where are stem cells found in adult humans, which can develop into many types of cells including blood cells?
Bone marrow
44
Name the tissue in plants where stem cells are found
Meristem
45
Why are stem cells useful to treat diseases?
They can be cloned and made to differentiate into most different types of human cells
46
Name the process by which an embryo is produced with the same genes as the patient so that stem cells can be removed and used to treat diseases
Therapeutic cloning
47
Give one risk of using stem cells to treat diseases
Possible transfer of viral infection
48
Give one reason why people might object to stem cell use for ethical or religious reasons
Because an embryo is killed, which is a potential life
49
Give one reason why plant growers might want to use stem cells to produce clones of plants
To prevent rare species from extinction; to produce large numbers of identical plants with specfiic features e.g. disease resistance
50
What is diffusion?
Spreading out of particles resulting in net movement from an area of higher concentration to an area of low concentration
51
Name two substances transported into and out of cells by diffusion
oxygen and carbon dioxide
52
Name the waste product that diffuses out of cells into blood plasma for excretion in the kidney
urea
53
Name three factors that affect the rate of diffusion
Difference in concentrations; temperature; surface area of membrane
54
Does a single-celled organism have a relatively large or small surface area to volume ratio compared to larger animals?
Large
55
Why can a single-celled organism rely on diffusion to meet it's needs (e.g. of oxygen) but a larger animal requires exchange surfaces and a transport system?
Because it has a larger surface ara to volume ratio.
56
Name the gas exchange surface in fish
Gills
57
What are the ways in which the small intestine is adapted for diffusion of small food molecules into the blood?
Villi to increase the surface area; good blood supply to maintain concentration gradient; thin walls
58
What are the ways in which the lungs in mammals are adapted for diffusion of oxygen into the blood and carbon dioxide back out?
Alveoli to increase surface area; walls are 1 cell thick; lots of capillaries to maintain concentration gradient
59
What are the ways in which the gills of fish are adapted for diffusion of oxygen into the blood and carbon dioxide back into the water?
Layered structure (filaments, lamellae) to increase the surface area; very thin
60
What are the ways in which all exchange surfaces (e.g. the lungs) are adapted for efficient diffusion
large surface area; efficient blood supply; thin membrane (short diffusion path); ventiliated (to maintain concentration gradient)
61
What is osmosis?
Diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
62
What is active transport?
Movement of substances from a more dilute solution to a more concentrated solution (against concentration gradient). Requires energy from respiration.
63
What is required for active transport which is not required for diffusion?
Energy from respiration (released in mitochondria)
64
Which organelle (cell part) might be more common in a cell carrying out active transport?
Mitochondria
65
Why do root hair cells need a supply of oxygen?
For respiration and to provide energy for active transport to take up minerals.
66
Give an example of active transport in plants
Taking up mineral ions from the soil via root hair cells from very dilute solutions
67
Give an example of active transport in animals
Absorbing sugar from low concentrations in the gut into the blood which has a higher sugar concentration