cell structure and transport Flashcards
1
Q
What are living things made up of?
A
Cells
2
Q
What are most cells too small to be seen with?
A
naked eye
3
Q
What are microscopes used for?
A
magnifying small objects
4
Q
What do light microscopes use to form an image?
A
a beam of light
5
Q
Up to what number can light microscopes magnify to?
A
2000x
6
Q
Up to what number can school microscopes magnify to?
A
400x
7
Q
What can light microscopes be used to view?
A
living objects
8
Q
What are positives of light microscopes?
A
relatively cheap and easy to carry around
9
Q
What do electron microscopes use to form an image?
A
a beam of electrons
10
Q
Up to what number can electron microscopes magnify to?
A
2000000x
11
Q
What can’t be electron microscopes be used for?
A
living objects
12
Q
What are negatives of the electron microscope?
A
very expensive and need to be kept in special conditions
13
Q
What are the two types of electron microscope?
A
transmission electron microscope and scanning electron microscope
14
Q
What forms the image in a typical school microscope?
A
beam of light
15
Q
What kind of image does a transmission electron microscope give?
A
2D images
16
Q
What kind of image does a scanning electron microscope give?
A
3D images
17
Q
Does a scanning electron microscope or transmission electron microscope give lower magnification? Why?
A
scanning electron microscope because 3D images
18
Q
What is resolving power?
A
the ability to distinguish closely spaced objects
19
Q
What is the resolving power of a light microscope?
A
200 nm
20
Q
What is the resolving power of an transmission electron microscope?
A
0.2 nm
21
Q
Does an electron microscope or a light microscope have better magnification and resolving power?
A
electron
22
Q
What is the equation that links image size, object size and magnification?
A
magnification = image size / object size
23
Q
How do you rearrange the equation to get object size = ?
A
object size = image size / magnification
24
Q
What is 1 km in m?
A
1000m
25
What is 1 m in cm?
100cm
26
What is 1 cm in mm?
10mm
27
What is 1 mm in micrometres?
1000 micrometres
28
What is 1 micrometre in nanometres?
1000 nanometres
29
What size do animal cells range from and to?
10 - 30 micrometres
30
What is function of the nucleus?
control cells activities
31
What is the size of the diameter of a nucleus?
10 micrometres
32
What is within the nucleus?
genes on chromosomes
33
What do the genes on chromosomes carry?
instructions for making proteins
34
What is the cytoplasm?
a liquid gel where organelles are suspended, where many chemical reactions take place
35
What is the function of the cell membrane?
control movement in and out of the cell
36
What is an example of something the cell membrane moves into a cell?
glucose and mineral ions
37
What is an example of something the cell membrane moves out of the cell?
urea and hormones
38
What is the function of the mitochondria?
energy is transferred here during aerobic respiration
39
What is the size range of a mitochondrion?
1-2 by 0.2-0.7 micrometres
40
What is the function of the ribosomes?
where protein synthesis occurs
41
In which part of the cell is energy transferred to during respiration?
mitochondria
42
What are algae?
simple aquatic organisms that have many features similar to plant cells
43
Are plant cells of animal cells bigger?
plant cells
44
What is the size range of a plant cell?
10-100 micrometres
45
What is the function of the cell wall?
extra support
46
What is the cell wall made out of and what does this do?
cellulose, makes it rigid
47
What is the function of a chloroplast?
absorb light to make food by photosynthesis
48
What does the chloroplast contain?
chlorophyll
49
What is the function of a permanent vacuole?
keep cell rigid to support the plant
50
What does the vacuole contain?
cell sap
51
What microscope can you use to look at algae, animal, plant and elodea cells?
light
52
Do onion cells have chloroplats?
no
53
Why do onion cells not look green?
no chloroplast, no chlorophyll
54
What kind of kingdoms are eukaryotic?
animals, plants, fungi and protista
55
What do the eukaryotic cells contain?
cell membrane cytoplasm nucleus
56
What does the nucleus contain in a eukaryotic cell?
chromosomes
57
What are chromosomes made of?
genetic material called DNA
58
What is an example of a prokaryotic cell?
bacteria
59
What are bacteria?
single-celled living organisms
60
What is the size range of a bacteria?
0.2-2 micrometres
61
What do prokaryotic cells have?
cell membrane, cell wall surrounding the cytoplasm
62
Why is the cell wall different in a prokaryote rather than in a plant cell?
isn't made of cellulose
63
Does bacteria have a nucleus?
no
64
Where is the genetic material found in a prokaryote?
in cytoplasm as a long circle of DNA
65
What do some prokaryotic cells contain?
plasmids
66
What are plasmids?
extra small circular rings of DNA
67
What other things do some bacteria contain?
protective slime capsule and flagella
68
What is the flagella for?
movement
69
What is the slime capsule for?
protection
70
Are all bacteria harmful?
no
71
Can bacterial colonies be seen with the naked eye?
yes
72
What are large organisms made up of?
many cells
73
What do cells do as the organism develops?
become specialised to perform a particular function
74
As cells become specialised, what do the also do?
differentiate
75
Where can specialised cells work in?
individually, part of tissue, organ or organism
76
What do muscle cells contain and why?
many mitochondria as they require a lot of energy
77
What are nerve cells specialised to do?
carry electrical impulses around the bodies of animals
78
What do nerve cells contain?
dendrites, axon, nerve endings or synapses, many mitochondria
79
What are dendrites in nerve cells for?
make connections with other cells
80
What is an axon for?
carry impulse from one place to another
81
What are synapses for?
pass impulses across by producing transmitter chemicals
82
What are many mitochondria in the synapses for?
transfer the energy needed to make the transmitter chemicals
83
What can muscle cells do?
contrast and relax
84
What kind of muscle cells are found in your muscles that enable your body to move?
striated
85
Where are smooth muscle cells found?
tissues of the digestive system
86
Why are smooth muscle cells found in the tissue of the digestive system?
to contract to move food along the gut
87
What do muscle cells have?
proteins, many mitochondria, store of glycogen
88
What do the proteins in muscle cells do?
slide over each other
89
What are the many mitochondria for in muscle cells?
transfer energy needed for chemical reactions
90
What is the store of glycogen in muscle cells for?
can be broken down to be used in respiration to transfer energy
91
Muscle cells contain a lot of mitochondria. Why?
mitochondria transfer energy during aerobic respiration, muscle cells need energy to contract
92
Which organ system contains nerve cells?
nervous system
93
What are 3 examples of specialised cells in animals?
nerve, muscle and sperm cells
94
What do sperm cells carry?
genetic information from the male parent
95
What are sperm cells specialised to do?
move through water or the female reproductive system to reach the egg
96
What are sperm cells trying to reach?
the female egg
97
What do sperm cells contain?
a long tail, middle section full of mitochondria, acrosome, large nucleus
98
What does the long tail in a sperm cell do?
whips from side to side to move sperm
99
What is the middle section full of mitochondria in a sperm cell for?
transfer energy needed by the tail to move
100
What is the acrosome in a sperm cell for?
store digestive enzymes to break down the outer layers of the egg
101
What is a large nucleus in a sperm cell for?
contain genetic information
102
What are 4 examples of specialised cells in plant cells?
root hair cells, photosynthetic cells, xylem cells, phloem cells
103
Where do root hair cells occur?
in the tips of the roots
104
What are root hair cells for?
increase surface area of the root so that it can absorb water and mineral ions efficiently
105
To what are root hair cells close to?
the xylem tissue
106
What specialised structures do the root hair cells contain?
large permanent vacuole, many mitochondria
107
For what use is the large permanent vacuole in a root hair cell?
speeds up movement of water by osmosis from soil across the root hair cell
108
For what use are the many mitochondria in a root hair cell?
transfer the energy needed for active transport of mineral ions into the root hair cells
109
What can plant make with photosynthesis?
their own food
110
What are the specialised structures that photosynthetic cells contain?
chloroplasts, large permanent vacuole
111
Where are photosynthetic cells usually found?
continuous layers in the leaf and outer layers of stems
112
What are the 2 main functions of the xylem cells?
transport water and mineral ions from the roots to the stems and leaves , support the plant
113
Are xylem cells living when they are first formed?
yes
114
What chemical builds up in spirals in the cell walls of the xylem?
lignin
115
Where does lignin build up in xylem cells?
the spiral of the cell walls
116
In the xylem, the cells die, what do they leave behind?
long hollow tubes
117
What do the long hollow tubes allow to happen in xylem cells?
water and mineral ions to move up the tubes
118
What makes the tubes of xylem very strong?
spirals and lignins
119
What do the spirals and lignins do to the xylem?
make it strong
120
What does the phloem do?
transports food made by photosynthesis to the rest of the plant
121
Phloem cells form tubes but don't become what, unlike the xylem?
lignified
122
What do the cell walls between phloem cells break down to form?
sieve plates
123
What do phloem cells lose a lot of and what helps to keep them alive?
lose a lot of their structures but kept alive by companion cells
124
What do the companion cells around the phloem contain?
mitochondria that transfer energy to aid the movement of dissolved food up the phloem
125
How do molecules in gases and liquids move around?
randomly
126
Why do molecules in gases and liquids move around randomly?
because of the energy they have
127
What is diffusion?
the spreading out of particles of a gas, or of any substance in solution ( a solute)
128
What does the net movement into or out of cells depend on?
the concentration of particles on each side of the cell membrane
129
What will be produced because of the particles moving randomly?
a net ( overall ) movement
130
What does the net movement go from and to in diffusion?
high concentration to low concentration
131
What is the difference in concentration between 2 areas called?
the concentration gradient
132
What happens to the diffusion if there is a larger difference in concentration?
faster the rate of diffusion
133
What determines the net movement of particles across a cell membrane?
concentration of particles on either side of the cell membrane
134
What does an increase in temperature mean in diffusion?
causes particles to move faster
135
What happens when the particles diffuse faster?
increases the rate of diffusion
136
What are 4 examples of diffusion?
- the diffusion of oxygen and glucose into the cells of the body from the bloodstream for respiration
- the diffusion of carbon dioxide into actively photosynthesising plant cells
- the diffusion of oxygen and carbon dioxide in opposite directions in the lungs, known as gas exchange
- the diffusion of simple sugars and amino acids from the gut through cell membranes
137
Describe what is meant by gas exchange in the lungs
the diffusion of carbon dioxide and oxygen in opposite directions
138
If both type of particles can pass through a membrane, what can you call it?
freely permeable
139
What does a steep concentration gradient mean in terms of diffusion?
the bigger the difference, the steeper the concentration gradient and the faster the molecules of a substance will diffuse
140
What does a shallow concentration gradient mean in terms of diffusion?
if a gradient is shallower, it's a meaning that there is a less difference in concentration between the 2 areas causing the particles to diffuse more slowly
141
What is the full definition of diffusion?
The spreading out of particles of any substance, in a solution or gas, resulting in a net movement from an area of higher concentration to an area of lower concentration, down a concentration gradient
142
What can the rate of diffusion be affected by?
difference in concentrations, temperature and the surface area that is available
143
What kind of dissolved substances can move in and out of cells by diffusion?
glucose and urea, gases such as oxygen and carbon dioxide
144
What is osmosis?
diffusion of water across a partially permeable membrane
145
What is a similarity between osmosis and diffusion?
the movement of particles is random and requires no energy from the cell
146
What does the water move from and to?
a region of high water concentration to a region of lower water concentration
147
What is a high water concentration?
a dilute solution
148
What is a low water concentration?
more concentrated solution
149
What is the cell membrane in osmosis?
partially permeable
150
If the two solutions have the same concentration, what are they called?
isotonic
151
If the solution is more concentrated ( has more solute and relatively less water ), what is it called?
hypertonic
152
If the solution that is more dilute ( has relatively more water and less solute ), what is it called?
hypotonic
153
What will animal cells that are surrounded by a hypotonic solution do and why?
swell and possibly burst because water moves into the cell by osmosis
154
What will animal cells that are surrounded by a hypertonic solution do and why?
shrink as water moves out of the cell by osmosis
155
What do animals need to control the concentration of the solutions around the cells to avoid bursting or shrinking?
complex mechanisms
156
Why do animals need complex mechanisms in terms of osmosis?
to control the concentrations to the solutions around the cells to avoid bursting or shrinking
157
Why do animals control the concentration of solution around the cell by the use of complex mechanisms?
avoid bursting or shrinking
158
When does turgor pressure occur?
when no more water can enter a cell due to the pressure inside
159
What are the steps of a cell gaining turgor pressure?
- water moves into the cell by osmosis
- the vacuole swells
- the cytoplasm is pressed against the cell wall
- the cells become rigid
- the leaves and stems become rigid
160
