Topic 1 - Cell Biology Flashcards
1
Q
Give an example of a prokaryote cell.
A
Bacterium
2
Q
Give an example of a eukaryote cell.
A
Plants and animals
3
Q
What is a prokaryote?
A
Single celled organism.
4
Q
Give three features of a eukaryote cell.
A
Cell membrane
Cytoplasm
Generic material in nucleus
5
Q
Which are bigger: prokaryotes or eukaryotes?
A
Eukaryotes
6
Q
Give three features of a prokaryote.
A
Cell membrane
Cell wall
Cytoplasm
7
Q
Where is the genetic material enclosed in a prokaryote?
A
In a single DNA loop (aswell as possible plasmids)
8
Q
What is a plasmid?
A
Small rings of DNA
9
Q
What is the formula for magnification?
A
Magnification x Real size = image size
10
Q
What do most animals cells have inside them (features)?
A
- nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
11
Q
What do most plant cells have inside them (features)?
A
- nucleus
- cytoplasm
- mitochondria
- Ribosomes
- cell membrane
- chloroplast
- permanent vacuole filled with sap
12
Q
What is the feature of plant and agal cells that strengthens the cells?
A
Cell wall
13
Q
What cells are specialised in animals?
A
Sperm cells
Nerve cells
Muscle cells
14
Q
What cells are specialised in plants?
A
Root hair cells
Xylem
Phloem
15
Q
How are sperm cells specialised?
A
For reproduction:
Long tail + stream lined head (to help it swim)
Lots of mitochondria (give energy)
Carries enzymes (to digest through egg cell)
16
Q
What does the cytoplasm do?
A
Gel-like substance where most chemical reactions happen
17
Q
What does the cell membrane do?
A
Controls movement in and out of cell
18
Q
What does mitochondria do?
A
Where most of the reactions for aerobic respiration happens to transfer energy
19
Q
What do the ribosomes do?
A
Makes proteins
20
Q
What is the cell wall made of?
A
Cellulose
21
Q
What is the permanent vacuole made from?
A
Cell sap
22
Q
What does chloroplast do?
A
It allows photosynthesis to happen to make food for the plant
23
Q
What does chloroplast contain?
A
Green substance called chlorophyll which absorbs light for photosynthesis
24
Q
What is the function of sperm cells?
A
To get male DNA to female DNA
25
What is the function of nerve cells?
To carry electrical signals around the body
26
How are nerve cells specialised?
For rapid signalling:
Long (to cover more distance)
Have branched connections (to connect to other nerve cells and form a network)
27
What is the function of muscle cells?
To contract quickly
28
How are muscle cells specialised?
Long (more space to contract)
| Contain lots of mitochondria (generate energy needed for contraction)
29
What is the function of root hair cells?
To absorb minerals and water
30
How are root hair cells specialised?
On surface of plant roots that grow into long hairs that stick into soil - large surface area to absorb water and mineral ions from soil
31
What are the functions of phloem and xylem cells?
To transport water and food around plants
32
How are phloem and xylem cells specialised?
Joined end to end to form tubes
Xylem are hollow (to allow flow through)
Phloem have very few sub cellular structures (to allow flow through)
33
What is cell differentiation?
The process by which cells change to become specialised for their job
34
What happens when cells differentiate?
They develop sub cellular structures and turn into different types of cells (allowing them to carry out specific functions)
35
When does differentiation occur in an animal cell?
At an early stage
| The ability to differentiate is then lost once specialised
36
When do plant cells differentiate?
Anytime as they retain the ability to differentiate throughout life
37
When do cells differentiate in mature (old) animals?
To repair or replace cells
38
Are stem cells differentiated?
No
39
How has the microscopy technique developed over time?
Used to be limited to the differences in magnification and resolution.
40
How do light microscopes work?
Use light and lenses to form images, let us see individual cells and large sub cellular structures like nuclei.
41
How do electron microscopes work?
Use electrons to form image, have a much higher magnification and resolving power the light microscopes. Can study cells in finer details (enabled scientists to find out more)
42
How often do bacteria multiply?
(By single celled division) every 20 mins if they have enough nutrients and are at a suitable temperature
43
Where can we grow bacteria?
Nutrient broth solution or on agar plates as colonies
44
Uncontaminated cultures of micro organisms are required for what investigation?
Investigating the action of disinfectants and antibiotics.
45
How do you sterilise the petri dishes and culture media for the aseptic technique?
Using a blue flame heat the inoculations hoop and mouth of bacteria bottle and Petri dish should be heated and then cooled to kill any unwanted bacteria
46
How should you put the lid on the Petri dish for the aseptic technique?
Secure with tape, but not sealed (to allow the bacteria to breathe) and stored upside down in the incubator to prevent condensation
47
What temperature should cultures be stored at in schools?
25 degrees Celsius
48
Where are chromosomes stored?
Nucleus
49
What are chromosomes?
Coiled up lengths of DNA
50
What do chromosomes carry?
A large number of genes found in pairs
51
What are the two stages of the cell cycle called?
1. Growth and DNA replication
| 2. Mitosis
52
Describe the stages of Growth and DNA replication the the cell cycle.
1. (Before division) a cell must grow and increase its amount of sub cellular structures
2. It then duplicates its DNA (so there is a new copy for each cell) these copies form X shaped chromosomes - each arm is an exact duplicate
53
Explain the stages of mitosis in the cell cycle.
1. Chromosomes line up at centre of cell and cell fibres pull them apart (the two arms go to opposite ends)
2. Membranes form around each of the sets (becoming the nuclei of the two new cells - nucleus has divided)
3. Cytoplasm and cell membrane divide producing two new daughter cells which are indentical
54
What are stem cells?
An undifferentiated cell of an organism that can produce lots more undifferentiated cells which can differentiate into other cells
55
What is the function of a stem cell in en embryo?
They have the potential to turn into any kind of cell, they can be cloned and made to differentiate
56
What can stem cells from adult bone marrow do?
From many types of cells including blood cells
57
What is the tissue in plants called that can differentiate into any type of plant cell quickly and economically?
Meristem tissue
58
Treatment with stem cells may be able to help which conditions?
Diabetes and paralysis
59
Under what terms can stem cells be used for medical treatment?
From therapeutic cloning: where embryos are produced with the same genes as the patient so they aren't rejected by the patients body.
60
What are the risks of using stem cells?
Transfer of viral infection
| Ethical or religious objections
61
Why is cloning useful for rare species of plants?
To protect them from extinction
62
What can farmers do to produce large numbers of genetically modified crops?
Clone plants that have special features (disease resistance)
63
What is diffusion?
The spreading out of particles from an area with high concentration to an area with lower concentration
64
How can substances move in and out of cells?
Via diffusion
65
Name some substances transported in and out of cells by diffusion.
Oxygen
Carbon dioxide
Waste product of urea (into blood plasma and to kidney for excretion)
66
Name three factors that will affect the rate of diffusion.
```
Surface area
Concentration gradient (difference in concentrations) Temperature
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67
Single celled organisms have large surface areas and low volumes to allow what?
Sufficient transport of molecules in and out of fpcell to meet its needs
68
What are surfaces and organ systems specialised for exchanging materials in multicellular organisms?
To allow sufficient molecules to be transported in and out of the cells to meet organisms needs
69
How is the effectiveness of an exchange surface increased?
Large surface area
Thin membrane (provides short diffusion path)
Efficient blood supply (animals only)
Being ventilated (gas exchange in animals)
70
How can water move across cell membranes?
Via osmosis
71
What is osmosis?
The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
72
What is active transport/how does it move substances?
Active transport moves substances from a more dilute solution to a more concentrated solution but AGAINST A CONCENTRATION GRADIENT
73
What is needed for active transport to be carried out?
Energy from respiration
74
What do plants require for healthy growth? And where do they get it from?
The need mineral ions, absorbed into plant root hair cells dip from very dilute solutions in the soil
75
What is needed for respiration and how is it transported?
Sugar molecules, absorbed from lower concentrations in the gut and into the blood which has a higher sugar concentration
