B1 Flashcards
(87 cards)
1
Q
1 kilometre is how many metres ?
A
1000
2
Q
1 metre is how many centimetres ?
A
100
3
Q
1 cm is how many millimetres ?
A
10
4
Q
1 mm is how many micrometres ?
A
1000
5
Q
1 micrometre is how many nanometres ?
A
1000
6
Q
How does a light microscope work ?
A
They use a beam of light to form an image of an object .
7
Q
What can a light microscope magnify up to ?
A
2000 times
8
Q
What has the electron microscope allowed us to do ?
A
We are now able to see and understand more about subcellular structures inside cells .
9
Q
How does an electron microscope work ?
A
a beam of electrons are used to form an image and can magnify up to 2,000,000 times
10
Q
What are three disadvantages of the electron microscope ?
A
- They are very expensive
- They have to be kept at a specific temperature
- They are large
11
Q
If you are given an image of inside a cell , how do you calculate the magnification ?
A
magnification = size of image/size of real object
12
Q
What is the other equation of magnification ?
A
eyepiece lens x objective lens
13
Q
What is the objective lens ?
A
Used to magnify an image at different magnification levels
14
Q
What is the eyepiece lens ?
A
The lens you look through
15
Q
What is the definition of resolution ?
A
The ability to distinguish between two seperate points
16
Q
What are the main sub cellular structures in animal cell ?
A
Nucleas , cyctoplasm , cell membrane , ribosomes and mitochondria
17
Q
What is the function of the nucleas ?
A
controls everything that happens in the cell . Contains chromosomes which hold genes and DNA strands .
18
Q
What is the function of cyctoplasm ?
A
This is where all the chemical reactions take place which are needed for everyday life .
19
Q
What is the function of the cell membrane ?
A
This controls everything that comes in and out of the cell .
20
Q
What is the function of mitochondria ?
A
This is where aerobic respiration takes place , releasing energy for the cell .
21
Q
What is the function of a ribosome ?
A
This is where all the protein is made .
22
Q
What is algae ?
A
A simple aquatic organism . They make their own food by photosynthesis .
23
Q
What sub cellular structures does a plant cell contain ?
A
Nucleas , cell membrane , mitochondria , cyctoplasm , ribosomes , chloroplast , permanent vacuole and cell wall .
24
Q
What are the three extra sub cellular structures that a plant cell has ?
A
Chloroplast , permanent vacuole and cell wall
25
What is chloroplast ?
contains chlorphyll which absorbs sunlight for the plant
26
What is the permanent vacuole ?
A space in the cyctoplasm filled with cell sap . This is important for keeping the cells rigid to the support the plant .
27
What are examples of eukaryotic cells ?
Animal , plant cells , fungi and prostita
28
Is bacteria a single celled organism ?
yes
29
What is an example of a prokaryotic cell ?
Bacteria
30
What are four differences from a eukaryotic and prokaryotic cell ?
1. E - DNA is enclosed in a nucleas . whereas in P the DNA is spread out .
2. Cell wall in P does not contain cellulose , whereas in a plant cell it would .
3. P contain extra small DNA rings called plasmids .
4. Bacteria has flagellum at the back of their cell .
31
What is a specialised cell ?
A cell that is specialised for a specific function .
32
Does a plant cell differentiate at an early stage of development ?
No they can differentiate throughout their life .
33
How are nerve cells specialised ?
To carry out electrical impulses around the body . They provide a rapid communication system between different parts of the body .
34
What three things makes a nerve cell specialised ?
1. Lots of Dendrites which carry out electrical impulses around the body .
2. An axon that carries the nerve impulse from one place to another .
3. The synapses are adapted to pass the impul;se to another cell or btween a nerve cell and muscle in the body .
35
How are muscle cells specialised ?
They contract and relax
36
What three adaptations make a muscle cell specialised ?
1. They contain special proteins that slide over each other making the fibres contract .
2. They contain many mitochondria
3. They can store glycegon
37
What is the function of a sperm cell ?
To fertilise an egg
38
What three things make a sperm cell specialised ?
1. a long tail
2. The middle section is full with mitochondria
3. a large nucleas containing genetic information
39
What are the three main specialised cells in animal cells ?
Nerve , muscle and sperm cells .
40
What is the function of a root hair cell ?
The root hair cells help their plants to take up water and mineral ions more efficiently .
41
What three things make a root hair cell specialised ?
1. They greatly increase the surface area available for water to move into the cell .
2. They have a large permanent vacuole that speeds up the movement of water by osmosis from the soil .
3. They have many mitochondria that transfer energy needed for active transport .
42
What are three things that make a photosynthetic cell specialised ?
1. Contain structures like chloroplast which contains chloropyll .
2. They are usually placed in the leaf at the top so they can absorb as much sunlight as they can .
3. They have a large permanent vacuole that keeps the cell rigid .
43
What is a xylem cell ?
A transport tissue in plants that carries water and mineral ions from the roots to the highest leaves and shoots . it is also important in supporting the plant .
44
What are two ways in which xylem cells are adapted ?
1. The cells are dead , they form long hollow tubes that allow the water and mineral ions to move easily .
2. They contain a special chemical called lignin which builds up in spirals along the cell walls . This makes the plant strong .
45
What is a phloem cell ?
A specialised transport tissue that carries food made by photosynthesis around the body of the plant .
46
What are two adaptations of the phloem cell ?
1. They have sieve plates that allow water carrying dissolved foods to move freely up and down the tubes to where it is needed .
2. The cells are supported by companion cells that help them to keep them alive . The mitochondria of the companion cells transfer the energy needed to move dissolved foods up and down the phloem .
47
Why do we need diffusion ?
Your cells need to take in substances such as glucose and oxygen for respiration . To get rid of waste and to allow dissolved substances to move into and out of your body .
48
What is diffusion ?
Diffusion is the spreading out of particles of a gas or of any substance in a solution .
49
What is net movement ?
overall movement of particles
50
In diffusion what is the net movement of particles ?
from an area of high concentration to low concentration .
51
What are two gases that can enter cells by diffusion ?
Oxygen and carbon dioxide
52
What four things are affected by diffusion ?
Surface area
Temprature
Concentration gradient
Diffusion distance
53
What is the equation for net movement ?
Particles moving in - particles moving out
54
How does the small intestine increase its surface area ?
The small intestine folds itself which allows more particles to move through .
55
What is gas exchange ?
The diffusion of oxygen and carbon dioxide in opposite directions in the lungs
56
What is the most common adaptation to cells to increase the surface area ?
By folding up the membrane of the cell
57
What is osmosis ?
This is the movement of water molecules only, from an area of high water concentration to an area of low water concentration across a partially permeable membrane .
58
What is a partially permeable membrane ?
A membrane that lets some molecules through but not others .
59
What is water potential ?
Water potential is also known as water concentration .
60
What is a dilute solution ?
When the solute ( the substance that is dissolved ) is lower than the solvent ( like water )
61
What is the experiment used for osmosis ?
The potato experiment
62
What is the independent variable in the potato experiment ?
The solute concentration , sugar
63
What is the dependent variable in the potato experiment ?
The change in mass of potato cylinders
64
What are the two control variables in the potato experiment ?
Temperature and surface area of potato
65
What is the method used for the potato experiment?
1. Use a cork borer to cut 5 potato cylinders of the same diameter
2. Use a scalpel and ruler to trim each potato cylinder so they are all the same length
3. Measure the mass of each potato cylinder and record in a table of results
4. Measure 10cm cubed of each sugar or salt solution and pour into each boiling tube
5. Place the potato cylinders into each boiling tubes
6. Time how long the potato cylinders are in the tube for .
7. Remove the potatoes, blot dry and record the final mass
66
In the osmosis experiment what does a decrease in mass tell us ?
That the net movement of osmosis is out of the cell
67
What does the term isotonic mean in an animal cell in terms of osmosis ?
The amount of water inside and outside the is the same
68
What does the term hypertonic mean in terms of osmosis ?
This means that the movement of osmosis is out of the cell to a lower concentration of solution . It will become shrivelled
69
What does hypotonic mean in terms of osmosis ?
When water moves into the cell by osmosis it might burst
70
Why do plants rely on osmosis ?
To support their stems and leaves
71
What does turgid mean ?
When the balance of water in and out of the cell is normal
72
What does flaccid mean in a plant cell ?
When water moves out of the cyctoplasm
73
What is active transport ?
Active transport allows cells to move substances from an area of low concentration to an area of high concentration . This movement is against the concentration gradient .
74
Where does active transport happen in plants ?
Happens in the root hair cells from the soil to the surrounding roots
75
Where can active transport be seen in an animal cell ?
In the small intestine
76
What is needed for active transport to work ?
A lot of energy
77
How is the energy produced for active transport ?
Respiration
78
Does the ratio of surface area to volume ratio fall as objects get bigger ?
Yes
79
In a small object what is the surface area to volume ratio like ?
Larger surface area to volume ratio which means that their is a better exchange
80
In a large object what is the surface area to volume ratio like ?
Harder to exchange materials
81
The effectivness of an exchange surface can be increased by three things :
. Having a large surface area over which exchange can take place
. Having a thin membrane or being thin to provide a short diffusion path
. Having an efficient blood supply
82
What is an example of an adaptation of exchanging materials ? How are they adapted ?
Alveoli , have an enormous surface area and a very rich blood supply , for effective gas exchange
83
How are the villi adapted ?
They provide a large surface area and a rich blood supply
84
What is cystic fibrosis ?
Thick , sticky mucus in peoples lungs , gut and reproductive systems
85
How are fish adapted to exchange oxygen and carbon dioxide ?
Their gills
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