B1 - Cell Structure And Tranport Flashcards
1
Q
What are the basic units of measurement related to microscopy?
A
1 kilometre (km) = 1000 metres (m), 1 m = 100 centimetres (cm), 1 cm = 10 millimetres (mm), 1 mm = 1000 micrometres (µm), 1 µm = 1000 nanometres (nm)
A nanometre is 0.000 000 001 metres (or written in standard form as 1 × 10^-9 m)
2
Q
What is the maximum magnification of a light microscope?
A
Around 2000 times (x2000)
School microscopes usually only magnify several hundred times.
3
Q
When were the first light microscopes developed?
A
In the mid-17th century
4
Q
What is the primary function of a light microscope?
A
To use a beam of light to form an image of an object
5
Q
What are the types of electron microscopes and their features?
A
Transmission electron microscopes (2D images, high magnification and resolution), Scanning electron microscopes (3D images, lower magnifications)
Electron microscopes can magnify objects up to around 2000000 times.
6
Q
What is a key disadvantage of electron microscopes?
A
They are large, very expensive, and require special controlled environments
7
Q
How do you calculate the overall magnification of a microscope?
A
Multiply the magnification of the eyepiece lens by the magnification of the objective lens
8
Q
If the eyepiece lens is x4 and the objective lens is x10, what is the overall magnification?
A
x40
9
Q
What is the formula to calculate the size of an object under a microscope?
A
Size of image = magnification × size of real object
10
Q
What does resolution in microscopy refer to?
A
The ability to distinguish between two objects that are close together
11
Q
What is the resolving power of the best light microscopes?
A
About 200 nm
12
Q
What is the significance of the magnification triangle in microscopy?
A
It helps to calculate the size of an object based on the image size and magnification
13
Q
True or False: Light microscopes can only view dead specimens.
A
False
Light microscopes can magnify live specimens.
14
Q
Fill in the blank: The first light microscopes were developed in the ______ century.
A
17th
15
Q
What is the resolution between a light microscope and an electron microscope?
A
The resolution of an electron microscope is significantly higher than that of a light microscope.
16
Q
How do you calculate the magnification of a specimen?
A
Magnification can be calculated using the formula Icm = 10n.
17
Q
What is the equivalent of 1 mm in micrometers?
A
1 mm = 10 micrometers.
18
Q
What is the equivalent of 1 picometer in meters?
A
1 pm = 10^-12 meters.
19
Q
What parts are included in a light microscope?
A
- Eyepiece
- Coarse focus
- Objective lens
- Stage
- Fine focus
- Slide
- Light
20
Q
True or False: A light microscope can be used to observe live specimens.
A
True
21
Q
Fill in the blank: The formula to calculate real size is _______.
A
Icm = 10n
22
Q
What is the purpose of the coarse focus on a microscope?
A
To bring the specimen into general focus.
23
Q
What is the function of the objective lens in a microscope?
A
To magnify the specimen.
24
Q
Fill in the blank: The _______ holds the slide in place on the stage.
A
stage clips
25
What is the resolution between a light microscope and an electron microscope?
The resolution of an electron microscope is significantly higher than that of a light microscope.
26
How do you calculate the magnification of a specimen?
Magnification can be calculated using the formula Icm = 10n.
27
What is the equivalent of 1 mm in micrometers?
1 mm = 10 micrometers.
28
What is the equivalent of 1 picometer in meters?
1 pm = 10^-12 meters.
29
What parts are included in a light microscope?
* Eyepiece
* Coarse focus
* Objective lens
* Stage
* Fine focus
* Slide
* Light
30
True or False: A light microscope can be used to observe live specimens.
True
31
Fill in the blank: The formula to calculate real size is _______.
Icm = 10n
32
What is the purpose of the coarse focus on a microscope?
To bring the specimen into general focus.
33
What is the function of the objective lens in a microscope?
To magnify the specimen.
34
Fill in the blank: The _______ holds the slide in place on the stage.
stage clips
35
What is the formula to calculate the size of an object under a microscope?
magnification = size of image / size of real object
36
If the magnification is X40 and the size of the image is 1 mm, what is the size of the real object?
size of real object = size of image / magnification = 1 mm / 40 = 0.025 mm or 25 um
37
What is the magnified height of an average person using one of the best light microscopes?
about 3.5 km
38
What is the magnified height of an average person using an electron microscope?
about 3500 km
39
What is the resolving power of a light microscope?
about 200 nm
40
What is the resolving power of a scanning electron microscope?
about 10 nm
41
What is the resolving power of a transmission electron microscope?
about 0.2 nm
42
True or False: If two objects are closer than a certain distance, they will appear as one object.
True
43
Fill in the blank: The distance apart of two atoms in a solid substance is approximately _______.
0.2 nm
44
What is resolving power
The ability to distinguish between two separate points.
45
What is the average length of an animal cell?
10-30 µm
## Footnote
An average animal cell would take 100,000-300,000 cells to line up along the length of a metre ruler.
46
What controls all the activities of the cell?
The nucleus
## Footnote
The nucleus is surrounded by the nuclear membrane and contains genes on chromosomes.
47
What is the function of the cytoplasm?
It is a liquid gel where organelles are suspended and chemical reactions take place.
48
What does the cell membrane control?
The passage of substances into and out of the cell.
49
Where does aerobic respiration take place in a cell?
In the mitochondria.
50
What is the average size of mitochondria?
1-2 µm in length and 0.2-0.7 µm in diameter.
51
Where does protein synthesis occur?
In the ribosomes.
52
Fill in the blank: Plant cells have all the features of a typical animal cell, but they also have _______ needed for different functions.
additional features.
53
What are chloroplasts responsible for?
Photosynthesis.
54
What is the primary component of the plant cell wall?
Cellulose.
55
What is the average length range of plant cells?
10-100 µm.
56
True or False: Algae are classified as plants.
False
## Footnote
Algae are classified as part of the kingdom - the protista.
57
What is one key difference between plant and animal cells?
Plant cells make their own food through photosynthesis.
58
What is the function of the vacuole in plant cells?
Storage and maintaining turgor pressure.
59
What structure in animal cells is responsible for controlling the movement of substances?
The cell membrane.
60
What does the nucleus do?
Controls all the activities of the cell and is surrounded by the nuclear membrane that contained genes in chromosomes.
61
What is the role of the cytoplasm?
A liquid gel in which organelles are suspended and where most of the chemical reactions take place.
62
What is the role of the cell membrane?
Controls the passage of substances such as glucose and mineral Jon’s into the cells and urea or hormones out of the cell.
63
What is the mitochondria?
Aerobic respiration occurs
64
What are ribosomes?
Protein synthesis occurs
65
What do plant cells have that typical animal cells do not?
Features needed for their very different functions
## Footnote
Plant cells contain structures like chloroplasts and a cell wall.
66
How are algae classified in modern taxonomy?
Part of the kingdom protista
## Footnote
Algae were historically classified as plants.
67
What is the composition of the cell wall in plant and algal cells?
Cellulose
## Footnote
The cell wall strengthens the cell and provides support.
68
What is the function of chloroplasts in plant cells?
Photosynthesis
## Footnote
Chloroplasts contain chlorophyll, which absorbs light for food production.
69
Where are chloroplasts found in a plant?
In all the green parts of the plant
## Footnote
Root cells do not have chloroplasts as they do not photosynthesize.
70
What is the size range of a chloroplast?
3-5 micrometers long
## Footnote
Chloroplasts are relatively small organelles.
71
What is a permanent vacuole, and why is it important?
A space in the cytoplasm filled with cell sap that keeps cells rigid
## Footnote
This rigidity supports the plant structure.
72
What is the role of chlorophyll in plants?
To absorb light for photosynthesis
## Footnote
Chlorophyll is the green pigment found in chloroplasts.
73
Which type of microscope is used to examine plant cells?
Light microscope
## Footnote
A light microscope allows for the visualization of cell structures.
74
What structures should you see when examining a plant cell under a microscope?
Cytoplasm, nucleus, chloroplasts, permanent vacuole
## Footnote
Structures may vary between different types of plant cells.
75
True or False: All plant cells contain chloroplasts.
False
## Footnote
Root cells do not contain chloroplasts.
76
Fill in the blank: Algal cells perform photosynthesis and have features similar to _______.
Plant cells
## Footnote
Algae were historically classified alongside plants.
77
What is the primary function of the cell wall in plant cells?
To provide strength and support
## Footnote
The cell wall is made of cellulose.
78
Name two features unique to plant cells.
Chloroplasts and permanent vacuoles
## Footnote
These features are not found in animal cells.
79
What are eukaryotic cells
They all have a cell membrane, cytoplasm and genetic material enclosed in a nucleus.
80
What are bacteria?
Single cells living organisms and prokaryotes.
81
What do bacteria have?
Cytoplasm and cell membrane surrounded by cell wall but no cellulose
82
What are prokaryotic cells?
Genetic material is not enclosed in a nucleus and the bacterial chromosome is a single DNA loop found free in cytoplasm.
83
What can prokaryotic sometimes contain?
Plasmids - extra ring of DNA
Slime capsule
Flagella
84
What does a dime capsule do?
Protect the cell
85
What do flagellum do?
A long protein strand that helps them move.
86
What is a specialized cell?
A cell that becomes specialized to carry out particular jobs.
87
What are nerve cells like?
Carry electrical impulses around the body and provide a rapid communication system. They have lots of drendrites to connect to other nerves. An axon that carries the impulse. Never endings and synapses adapted to pass impulses between cells using transmitter chemicals. Lots of mitochondria to provide energy needed for transmitters. Myelin sheath for insulation.
88
What are muscle cells like?
They contract and relax and work together in muscles. They contract and relax in pairs to move the bones if a skeleton and contract the food through your gut. They contain special proteins that slide over each other making the fibers contract. They contain many mitochondria to transfer energy needed for chemical reaction. They store glycogen to be broken down and used in cellular respiration.
89
What are sperm cells like?
Usually released a long way from the egg they will fertilize and contain genetic information from male parent. They have a king tail to help them move through water or the reproductive system. The middle section is full of mitochondria to transfer energy needed in tail. Gagne acrosome stores digestive enzymes to break down outer layers of egg. Large nucleus containing genetic information.
90
Root hair cells
Found close to tops of growing roots. Need to take in lots of water and ions. Close to xylem. They greatly increase surface area available for water to move into cell. Have a large permanent vacuole to speed up movement of water in osmosis from soil to cell. Have many mitochondria that transfers energy needed for active transport of mineral ions.
91
Photosynthetic cells
Help plants make their own food by photosynthesis. Contain specialized chloroplasts containing chlorophyll that trap light needed. Usually positioned in continuous layers in leaves and outer stem to absorb as much light as possible. Large permanent vacuole to help keep cell rigid due to osmosis.
92
Xylem
Transports water and mineral ions from roots to leaves and shoots. Supports the plant. Cells are alive when first formed but lignin builds up spiral in cell wall and cells die forming long hollow tubes. The spirals and rings of lignin make them very strong and help withstand pressure.
93
Phloem
Specialized transport tissue carried food made by photosynthesis. Phloem cells are alive. Cell walls break down between cells to form sieve plates proteins that allow water carrying dissolved food to move up and down tubes. Lose a lot of internal structure but are supported by companion cells and mitochondria in these transfer energy to move food up and down plant.
94
What is diffusion used for?
Your cells need to take in substances like glucose and oxygen for respiration and get rid of waste products.
95
96
What is diffusion?
The spreading out of the particles of a gas or any substance in a solution resulting in the net movement of particles. This movement is from an area of higher concentration to an area of lower concentration.
97
What affects the rate of diffusion?
Difference in concentration, temperature and available surface area.
98
How does concentration affect rate of Diffusion?
If there is a big difference is concentration, diffusion will occur quickly and many particles will move randomly towards the area of low concentration. But, if there is only a small difference the movement will be quite slow.
99
What is the equation for net movement?
Net movement = particles moving in - particles moving out
100
What is the difference between two ages of concentration called?
Concentration gradient
101
How does the concentration gradient affect diffusion?
The steeper the gradient the faster the rate of diffusion. It occurs down a concentration gradient.
102
How does temperature affect rate of diffusion?
An increase in temperature means the particles in a gas or solution move around more quickly so diffusion occurs more rapidly.
103
How do substances such as sugars or glucose or gases move into and out of cells?
Diffusion across the cell membrane
104
Where does urea pass from and to?
From the liver cells into the blood plasma and is excreted by the kidneys
105
How does surface area affect rate of diffusion?
Increasing the surface area of the cell membrane increases the rate of diffusion.
106
What are partially permeable membranes?
Membranes that only let some types of particles through
107
What is a dilute solution of sugar?
Contains a high concentration of water and a low concentration of sugar
108
What is a concentrated solution of sugar?
Contains a low concentration of water and a high concentration of water
109
How does osmosis occur in a cytoplasm of a cell?
Cytoplasm is made of chemicals dissolved in water inside a partially permeable membrane and contains a fairly concentrated solution of salts and sugars. Water moves from a dilute solution to a concentrated solution
110
What is osmosis?
Water moves across a partially permeable membrane from a dilute solution to a concentrated solution
111
What is an isotonic solution?
When the concentration of solutes in the cell is the same as outside the cell.
112
What is a hypertonic solution?
When the concentration of solutes in the cell is lower than outside the cell.
113
What is a hypotonic solution?
When the concentration of solutes in the cell is the higher than outside the cell.
114
What happens if the solution outside the cell is too dilute - hypotonic?
The cell will swell and may burst
115
What happens if the solution outside the cell becomes too concentrated - hypertonic?
The cell will shrivel up and can no loner survive
116
Why do plants rely on osmosis?
To support their stems and leaves. Water moves into plant cells by osmosis causing the vacuole to swell and press the cytoplasm against the cell wall.
117
What is turgor?
When the pressure of the cytoplasm against the cell wall builds up as the vacuole grows until no more water can physically enter the cell. It makes the cells hard and rigid and so keeps the leaves and stems rigid and firm.
118
What happens if the solution outside a plant cell is hypertonic?
The water will leave the cell and they will no longer be firm and swollen and instead become flaccid as there is no longer any pressure. They may wilt.
119
What happens if loads of water is lost by osmosis from a plant cell?
The vacuole and cytoplasm shrink and eventfully the cell membrane pulls away from the cell wall. This is plasmolysis where cells die quickly unless the osmotic balance is resorted.
120
How do you investigate osmosis in plant cells?
Use an osmometer. Put plant tissue into different concentrations of salt or sugar solutions. If the plant tissue is placed in a hypotonic solution water will move in but if it is in a hypertonic solution water will move out. Use potato. Measure changes in mass. Pad of excess water on outside of plant before weighing.
121
What causes cystic fibrosis?
Active transport system in their mucus producing cells do not work properly.
122
What are the two ways that substances move into and out of cells?
Active transport and diffusion
123
What is active transport?
Substances move across a concentration gradient across a partially permeable membrane. Cells move from an area of low concentration to high.
124
125
What are some uses of active transport?
Cells can absorb ions from very dilute solutions and can move sugars and ions from one place to another.
126
What is a disadvantage of active transport?
Energy is needed for he system to carry a molecule across the membrane that is produced during cell respiration.
127
How are rates of respiration and rates of active transport linked?
If a cell resources and releases a lot of energy it can carry out lots of active transport. They have lots of mitochondria to do this.
128
What are some places active transport is needed?
Mineral ions in would found in dilute solutions entering root hair cells.
Sugar such as glucose is always actively absorbed out of your gut and kidney tubules into your blood.
129
130
What happens to glucose wheb needed for cell respiration?
The concentration of glucose in your blood is kept steady so sometimes it is higher than the concentration of glucose from your gut into your body against the concentration gradient.
131
How does surface area to volume ratio make a difference in transporting materials?
The smaller the surface area to volume ratio, the harder it is to exchange materials.
132
What happens if you have a small surface area to volume ratio?
Gases and food molecules can no longer reach every cell inside the organism by simple diffusion.
Metabolic waste cannot be removed fast enough to avoid poisoning the cells.
133
How does ratio of surface are to volume change as the object gets bigger?
It falls
134
How is the effectiveness of an exchange surface increased?
Having a large surface area
Having a thin membrane or providing a short diffusion path
Having an efficient blood supply to maintains steep concentration gradient
Being ventilated makes gas exchange more efficient
135
How are alveoli in the lungs adapted to gas exchange?
Enormous surface area
Rich blood supply
136
How are the villi in the small intestine adapted for diffusion?
Large surface area
Short diffusion path
Rich blood supply
137
How are leaves modified for gas and solute exchange?
Flat and thin
Presence of air spaces
Stomata provide a big surface area and maintain a steep concentration gradient
