Cell Biology Flashcards
1
Q
What are prokaryotes?
A
Small simple cells (a single-celled organism)
2
Q
What is an example of a prokaryote?
A
Bacteria
3
Q
What are eukaryotes?
A
Complex cells
4
Q
What type of cells are animal and plant cells?
A
Eukaryotes
5
Q
What does the nucleus do?
A
It contains the genetic information and controls the cell activities
6
Q
What are mitochondria?
A
Its the site where aerobic respiration takes place to release energy for the cell
7
Q
What is the cytoplasm?
A
The gel-like substance where most chemical reactions in the call take place
8
Q
What does the cytoplasm contain to control the reactions?
A
Enzymes
9
Q
What does the cell membrane do?
A
It holds the cell together and controls what enters and leaves the cell
10
Q
What are ribosomes?
A
The site of protein synthesis (where proteins are made)
11
Q
What does the vacuole do?
A
It contains cell sap and helps support the cell
12
Q
What is the cell wall made of?
A
Cellulose
13
Q
What does the cell wall do?
A
It helps support and strengthen the cell, giving it shape
14
Q
What does chloroplast contain?
A
Chlorophyll
15
Q
What is chlorophyll?
A
The green pigment which absorbs light energy for photosynthesis
16
Q
What are chloroplasts?
A
The site where photosynthesis occurs
17
Q
What organelles are in plant cells but NOT in animal cells?
A
Vacuole
Cell Wall
Chloroplasts
18
Q
What organelles are in BOTH plant cells and animal cells?
A
Cell membrane Nucleus Cytoplasm Ribosomes Mitochondria
19
Q
What does a bacteria cell NOT contain?
A
Mitochondria
Chloroplasts
Nucleus
20
Q
What does a bacteria cell contain?
A
Ribosomes Plasmids Strand of DNA Cell membrane Cell wall Cytoplasm
21
Q
What do bacteria cells have instead of a nucleus?
A
Plasmids and a strand of DNA
22
Q
Microscopy equation …..
A
Image Size = Actual size x Magnification
23
Q
What is iodine solution?
A
A stain
24
Q
Why are stains used in microscopy?
A
To highlight cell structures by adding colour to them
25
1000 um =
1 mm
26
1mm =
1000 um
27
10000 um =
1 cm
28
1 cm =
10000 um
29
What microscope can view living objects?
Light
30
In which microscope are colours visible?
Light
31
Which microscope produces a 3D image?
Electron
32
Why are light microscopes useful?
They are small, portable, easy to use and have simple preparation
33
What is differentiation?
The process by which a cell changes to become specialised for its job
34
What are cells that differentiate in mature animals mainly used for?
Repairing and replacing cells
35
What are undifferentiated cells known as?
Stem cells
36
What is the function of a sperm cell?
To get male DNA to the female DNA, fertilise an egg
37
Where are stem cells found?
In the bone marrow or human embryos
38
How are sperm cells adapted for reproduction?
Long tail + streamlined head to help swim to the egg
Lots of mitochondria to provide the energy needed
Carries enzymes to digest through the cell membrane
39
What is the function of a nerve cell?
To carry electrical signals from one part of the body to another
40
How are nerve cells adapted for rapid signalling?
Long to cover more distance
| Branched connections to connect to other nerve cells and form a network throughout the body
41
What is the function of a muscle cell?
To contract quickly
42
How are muscle cells adapted for contraction?
Long so they have space to contract
| Lots of mitochondria to generate energy needed for contraction
43
What is the function of a root hair cell?
To absorb water and minerals at the roots of plants
44
How are root hair cells adapted for abosorbing water and minerals?
Long 'hairs' so it has a big surface area for absorbing the minerals and water
Sticks out into the soil
45
What are the function of phloem and xylem cells?
To transport substances, such as food and water, around plants
46
How are phloem and xylem cells adapted to transport substances?
Long and joined end to end
Xylem - hollow in the centre
Phloem - few subcellular substances so stuff can flow through them
47
What does the nucleus contain?
Genetic information in the form of chromosomes
48
What are chromosomes?
Coiled up lengths of DNA
49
What does each chromosome carry?
A large number of genes
50
What do genes crontrol?
The development of different charcateristics
51
How many chromosomes do body cells have?
23 pairs - 46
52
Why does mitosis take place?
To make new cells for growth, development and repair - to replace damaged cells
53
What does mitosis result in?
2 new daughter cells that are genetically identical to the parent cell
54
What is the first thing the cell does during mitosis?
The cell grows and increases the amount of subcellular substances and duplicates its DNA
55
During mitosis, each of the chromosomes are an ______ ________ of the other
Exact duplicate
56
What do the chromosomes do before the cell is divided during mitosis?
They line up in the centre of the cell
57
What pull the chromosome arms apart during mitosis?
Cell fibres
58
What are the last things to divide during mitosis?
The cytoplasm and the cell membrane
59
Once the chromosomes are divided during mitosis, what happens to the sets of chromosomes?
Membranes form around the chromosomes - nuclei form for new cells
60
What is binary fussion?
How bacteria cells replicate
61
How many bacteria cells are needed for binary fission?
1 - asexual reproduction
62
What is the DNA of cells after binary fission like?
Both cells have one copy of the circular DNA but a variable number of copies of the plasmid(s)
63
What can embryo cells turn into?
Any type of cell
64
What can stem cells from the bone marrow become?
Specific cells e.g. blood cells
65
What is therapeutic cloning?
When the embryo is made to have the same genetic information as the patient - not rejected by the body
66
What is a risk of therapeutic cloning?
The stem cells grown in the lab may become contaminated with a virus and make the patient sicker
67
Where are stem cells found in plants?
In meristems
68
What can cells in meristem tissues differentiate into?
Any type of plant cell
69
What can meristem cells be used to produce?
Clones of whole plants quickly and cheaply
70
What can meristem cells be used to prevent?
Rare species from being wiped out
71
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration across a semi-permeable membrane
72
The difference in concentration is called the ...
Concentration gradient
73
How does a higher temperature effect the rate of diffusion?
It gives a faster diffusion rate as the particles have more energy and therefore move around faster
74
What can diffuse across a cell membrane?
Small molecules such as oxygen, glucose, amino acids and water
75
What can't fit through the cell membrane?
Big molecules like starch and proteins
76
How does a larger surface effect the rate of diffusion?
It increases the rate of diffusion because more particles can pass through at once
77
What is osmosis?
The movement of water molecules across a partially permeable membrane, from an area of high concentration of water to an area of low concentration of water
78
What is active transport?
The movement of particles against a concentration gradient, from an area of low concentration to an area of high concentration
79
What is required for active transport to take place?
Energy from respiration
80
Where does active transport take place?
In the root hair cells
| In the gut
81
Why does active transport take place in root hair cells?
Because the concentration of minerals is usually higher in the cell than in the soil, so it can't use diffusion
82
What happens to the concentration of water when minerals and ions move into the root hair cell? What does this cause?
There is a low concentration of water inside the cell and a higher concentration in the soil so the water particles move into the cell via osmosis
83
When is active transport used in the gut?
When there is a lower concentration of nutrients in the gut but a higher concentration of nutrients in the blood
84
What gas exchange takes place in lungs?
Oxygen into the blood and carbon dioxide out of the blood
85
How are the lungs adapted for gas exchange?
Contains air sacs (alveoli) which gives it a large surface area
Has a moist lining for dissolving gases
Very thin walls
A good blood supply
86
What exchange takes place in the small intestine (gut)?
Nutrients and glucose are absorbed into the blood supply
87
How is the small intestine adapted for diffusion?
It is covered in villi - to increase the surface area and therefore absorbed more easily
Single layer of surface cells
Good blood supply - to assist quick absorption
88
What is the underneath of a leaf covered in? Why?
Stomata
| So carbon dioxide can diffuse in through it
89
What diffuses out through the stomata?
Oxygen and water vapour
90
What controls the size of the stomata?
Guard cells
91
What do guard cells do if more water is being lost than replaced by the roots?
They close the stomata
92
What increases the exchange surface area of a leaf?
The flattened shape of the leaf
| The air spaces inside the leaf
93
How are gills adapted for gas exchange?
Each gill is made of lots of gill filaments (thin plates) - increase surface area
Gill filaments covered in lamellae (tiny structures) - increases surface area
Lots of blood capillaries - good supply of blood
Thin surface layer of cells
94
How are exchange surfaces adapted to maximise effectiveness:
A thin membrane
Large surface area
Lots of blood vessels (in animals)
Ventilated (in animals)
