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B2 - scaling up Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what care new cells needed for?

A

growth and repair

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2
Q

what is diffusion?

A
  • the net movement of particles from an area of higher concentration to an area of lower concentration
  • a consequence of the random movement of individual particles, until the molecules are evenly spread out and a dynamic equilibrium is reached
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3
Q

in what states must the particles be if they are going to be able to diffuse?

A
  • gas
  • liquid
  • in solution
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4
Q

how does difference in concentrations affect the rate of diffusion?

A

bigger difference = faster rate as particles collide more often/steeper slope

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5
Q

how does a larger surface area affect the rate of diffusion?

A

faster because there’s more surface area to diffuse to

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6
Q

how does a shorter distance affect the rate of diffusion?

A

there is less area for the particles to diffuse to/they can diffuse more quickly if they aren’t going far (less to travel)

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7
Q

how does a higher temperature affect the rate of diffusion?

A

the particles can move faster as they have more energy to move and collide

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8
Q

how does a barrier which is permeable to a substance affect the rate of diffusion?

A

faster if permeable diffusion can happen

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9
Q

true or false: molecules are able to diffuse because they are constantly moving around

A

true

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10
Q

true or false: only molecules in liquids and gases can diffuse

A

true

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11
Q

true or false: diffusion is the movement of molecules from an area of low concentration to an area of high concentration

A

false

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12
Q

true or false: molecules move down a concentration gradient during diffusion

A

true

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13
Q

true or false: molecules diffuse until they are evenly spaced apart

A

false

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14
Q

true or false: diffusion requires energy

A

true

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15
Q

what is osmosis?

A

the nett movement of water molecules from an area of high water potential to an area of low water potential through a selectively permeable membrane

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16
Q

what is a selectively permeable membrane?

A

a membrane that only lets certain molecules pass through and stops others

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17
Q

what’s the name for a concentrated solution?

A

hypertonic solution

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18
Q

what’s the name for a dilute solution?

A

hypotonic solution

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19
Q

what is a concentrated solution?

A

a lot of solute molecules (e.g. sugars or salts) dissolved in little water

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20
Q

what is a dilute solution?

A

very few solute molecules dissolved in lots of water

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21
Q

what happens to a animal cell in a hypertonic solution?

A

it becomes crenated

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22
Q

what happens to a plant cell in a hypertonic solution?

A

it becomes plasmolysed

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23
Q

what happens to a plant cell in an isotonic solution?

A

it becomes flaccid

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24
Q

what happens to a plant cell in a hypotonic solution?

A

it becomes turgid

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25
Q

what happens to a animal cell in a hypotonic solution?

A

lysis

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26
Q

what does being crenated mean?

A

shrivelled

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27
Q

what does being plasmolysed mean?

A

the cell has lost so much water that the cytoplasm pulls away from the cell membrane

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28
Q

what does lysis mean?

A

the cell swells up until it bursts open (bursts because it doesn’t have a cell wall)

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29
Q

why do plant cells become turgid rather than experience lysis?

A

the cell wall stops it from bursting

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30
Q

how do you calculate percentage change?

A

(new result-original result)/original result x100

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31
Q

what does active transport mean?

A

the transport of substances using energy in the form of ATP, up or against the concentration gradient (uses transport proteins); not across a membrane

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32
Q

what do plants need all the time?

A

mineral ions

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33
Q

how are root hair cells adapted to their function?

A

it has a large surface area to provide contact with soil water and also thin walls so that the movement of water is not restricted

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34
Q

does active transport require energy?

A

yes

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35
Q

how do plants take up mineral ions?

A

to take up mineral ions, the ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil; then active transport occurs across the root so the plant takes in the ions it needs from the soil around it

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36
Q

what is the function of transport proteins?

A

they are found in the cell membrane and help in active transport of substances in and out of the cell

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37
Q

what occurs during the cell cycle?

A
  1. DNA replication
  2. movement of chromosomes
  3. cytokinesis
  4. growth of daughter cell
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38
Q

which enzyme carries out DNA replication?

A

helicase

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39
Q

how is DNA replication carried out?

A
  • the DNA unwinds and unzips
  • following the complementary base pairing rule, free DNA nucleotides line-up against the separated DNA strands
  • another enzyme called DNA polymerase joins the free nucleotides together
  • the DNA molecules now twist back into a double helix
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40
Q

what is mitosis?

A

a form of cell division which divides the chromosomes and the cell itself into 2 genetically identical daughter cells

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41
Q

what are the stages of the cell cycle?

A
  1. interphase
  2. prophase
  3. metaphase
  4. anaphase
  5. telophase
  6. cytokinesis
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42
Q

which are the named stages of mitosis?

A

prophase, metaphase, anaphase, telophase

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43
Q

what happens during interphase?

A

each chromosome replicates so it contains two identical chromatids

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44
Q

what happens during prophase?

A

chromosomes become visible by shortening and thickening
(chromosomes become present)

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45
Q

what happens during anaphase?

A

the two chromatids in each chromosome are pulled apart by spindle fibres to opposite poles of the cell
(pulled apart)

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46
Q

what happens during metaphase?

A

the chromosomes align up along the centre/equator of the parent cell, moved by spindle fibres
(in the middle)

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47
Q

what happens during telophase?

A

there are now two nuclei
(two collections of chromosomes are visible)

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48
Q

what happens during cytokinesis?

A

the cell splits in two to produce two daughter cells, each containing the same chromosomes
(vision or splitting of the cytoplasm)

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49
Q

what are genes?

A

sections of DNA

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50
Q

what is a specialised cell?

A

a cell adapted to perform a particular function

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51
Q

what are some examples of specialised cells?

A
  1. sperm cells
  2. fat cells
  3. red blood cells
  4. ciliated cells
  5. palisade cells
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52
Q

what is the function of a sperm cell?

A

transfers genetic material from the male to the ovum

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53
Q

how is the sperm cell adapted for its function?

A
  • flagellum; whips from side to side to propel the sperm
  • lots of mitochondria; respiration, to transfer energy from chemical stores so the flagellum can move
  • acrosome; stores digestive enzymes to break down the outer layers of the ovum to allow the sperm to transfer and incorporate its genetic material
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54
Q

what is the function of a fat cell?

A

to store fat (used as a source of energy), provide insulation and form a protective layer around some organs

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55
Q

how is the fat cell adapted for its function?

A
  • small layer of cytoplasm surrounding a fat reservoir
  • can expand up to 1000x their original size as they fill with fat
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56
Q

what is the function of a red blood cell?

A

to carry oxygen around the body (found in the blood which flows around the circulatory system)

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57
Q

how is the red blood cell adapted for its function?

A
  • contain haemoglobin (carries oxygen molecules)
  • no nucleus (more space to carry oxygen)
  • bi-concave shape which gives a large SA and the best chance of absorbing as much oxygen as they can
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58
Q

what is the function of ciliated cells?

A

to move mucus/liquid past the cells (found in lining of airways and fallopian tubes)

59
Q

how are ciliated cells adapted for their function?

A
  • cilia; hair-like projections that move
  • lots of mitochondria to provide energy from respiration for cilia to move
60
Q

what is the function of palisade cells?

A

to carry out photosynthesis (found in the top of the leaf)

61
Q

how are palisade cells adapted for their function?

A
  • lots of chloroplasts which contain the light absorbing pigment chlorophyll
  • regular shaped closely packed cells from a continuous layer for efficient and maximum absorption of sunlight
62
Q

what is a stem cell?

A
  • an undifferentiated cell
  • a cell that divides by mitosis forming cells which can differentiate and become specialised
  • a cell which can develop into any type of specialised cell
  • used by the body during development, growth and repair
63
Q

what are some different types of stem cell?

A
  • embryonic stem cells
  • adult stem cells
  • plant stem cells
64
Q

where do embryonic stem cells come from?

A

they are derived from 5-7 day old blastocysts

65
Q

how many cells can embryonic stem cells differentiate into?

A

they are totipotent; capable of generating any cell in the body (including any cells that make up the embryo or placenta)

66
Q

what does totipotent mean?

A

can differentiate into anything

67
Q

what happens to cells when an adult is fully grown?

A

once an animal is fully grown, many adult cells remain in a non dividing state

68
Q

where are adult stem cells found?

A

in various body tissues e.g. brain, bone marrow, skin and liver

69
Q

how many different cells can adult stem cells differentiate into?

A

they are able to develop into some different types of cell, but not as many as embryonic stem cells

70
Q

where are plant stem cells?

A

plant stem cells are in the meristems of the plant; these are the regions of the plant that continue to grow throughout their lives (root tips and shoot tips)

71
Q

what do meristems look like?

A

meristems look very different to normal plant cells; they are small compared to other plant cells, they have very thin walls, small vacuoles and no chloroplasts

72
Q

what are some advantages of using embryonic stem cells?

A
  • could help to save existing lives (can be used to treat a range of illnesses)
  • not physically painful to the donor
73
Q

what are some disadvantages of using embryonic stem cells?

A
  • it prevents new lives from forming (religious groups etc are against it)
  • it’s easier to use those that are grown in a body because it’s more predictable
  • not very many willing donors
74
Q

what are alveoli?

A

small air sacs in the lungs that serve as the gaseous exchange surface, they provide a large surface area for efficient exchange

75
Q

what is the aorta?

A

the main artery that takes oxygenated blood away from the heart to the body

76
Q

what is an atrium?

A

the upper chamber of the heart that receives the blood from the veins

77
Q

what does biconcave mean?

A

describes the shape of red blood cells which increases the surface area for gaseous exchange

78
Q

what is blood?

A

a tissue that contains red blood cells, white blood cells, plasma and platelets

79
Q

what is a double circulatory system?

A

a circulatory system found in mammals in which the blood passes through the heart twice in a full body circuit

80
Q

what is the heart?

A

the organ that pumps blood around the body

81
Q

what is plasma?

A

a pale yellow liquid found in the blood that carries water, enzymes, salts, nutrients, proteins, urea and hormones

82
Q

what is the pulmonary artery?

A

the main artery that carries deoxygenated blood away from the heart to the lungs

83
Q

what is the pulmonary vein?

A

the main vein that carries oxygenated blood back to the heart from the lungs

84
Q

what are red blood cells?

A

cells in the blood that carry oxygen and remove carbon dioxide

85
Q

what is a single circulatory system?

A

a circulatory system in which the blood passes through the heart only once in a full body circuit

86
Q

what are valves?

A

structures found at each end of both ventricles that prevent back flow of blood (ensuring blood flows in one direction), valves can also be found in veins

87
Q

what is the vena cava?

A

the main vein that carries deoxygenated blood back to the heart from the body

88
Q

what are ventricles?

A

the lower chambers of the heart that receive blood from the atria and pump it to the arteries, the human heart has two ventricles

89
Q

what are villi?

A

small projections from the small intestine that increase the surface area for food absorption

90
Q

what is the relationship between size and SA:V?

A

as an organism gets bigger, it’s SA:V gets smaller

91
Q

how are amoeba adapted for substance exchange?

A

amoebas are single celled organisms and so have a very high SA:V, substances can diffuse directly in and out of the cell

92
Q

how are alveoli adapted for substance exchange?

A

air is moved into and out of your lungs when you breathe, ventilating the millions of tiny air sacs called alveoli; the alveoli have an enormous SA and a very rich blood supply, both of which make your lungs very effective for gas exchange

93
Q

how are villi adapted for substance exchange?

A

they increase the SA of the gut for absorption of food molecules

94
Q

how are flatworms adapted for substance exchange?

A

a worm’s respiratory surface is it’s skin, a flatworm will have a higher SA:V than a regular worm

95
Q

how are root hairs adapted for substance exchange?

A

plant roots have a very large SA, which is increased more by the root hair cells to make the uptake of water and mineral ions more efficient; water is constantly moved away from the roots in the transpiration stream, maintaining a steep concentration gradient into the cells

96
Q

how are leaves adapted for substance exchange?

A

plant leaves are modified to make gas and solute exchange as effective as possible; flat, thin leaves, the presence of air spaces in the leaf tissues and the stomata all help to provide a big SA, this maintains a steep concentration gradient for the diffusion of substances such as water, mineral ions and carbon dioxide

97
Q

how are fish gills adapted for substance exchange?

A

gills are made up of gill filaments; these are stacked up in a pile, at right angles to the filaments are gill lamellae (which increase the SA of the gills)

98
Q

what muscle tissue makes up most of the heart?

A

cardiac muscle

99
Q

explain why the muscular wall of the left ventricle is thicker than the right ventricle

A

the muscle in the left ventricle has to be very thick, to pump at a high pressure (through the aorta), this makes the blood travel all the way around your body

100
Q

what is the role of an artery?

A

blood is carried away from the heart under high pressure by the arteries, the blood is at high pressure due to the strong contractions of the heart

101
Q

how are arteries adapted?

A

to withstand the high pressure, the artery walls are thick and very muscular; the arterial wall will expand due to the force of a contraction then recoil to push the blood forward

102
Q

what is the role of a vein?

A

the veins return blood to the heart and have valves to prevent blood flowing backwards

103
Q

how are veins adapted?

A

blood pressure in the veins is very low, the veins have a large diameter which offers the least resistance to blood flow

104
Q

what is the role of a capillary?

A

capillaries link the arteries and veins ins tissues and organs; the network of capillaries means that every cell is close to a capillary for exchange of substances

105
Q

how are capillaries adapted?

A

the walls of the capillary are semipermeable and one cell thick to allow this

106
Q

what are the four components of blood?

A
  1. plasma
  2. red blood cells
  3. white blood cells
  4. platelets
107
Q

what is the function of plasma?

A
  • transports digested food, urea, hormones etc
108
Q

what is the function of red blood cells?

A
  • biconcave shape
  • no nucleus
  • transports oxygen
109
Q

what is the function of white blood cells?

A
  • part of immune response
  • ingesting pathogens
  • producing antibodies
110
Q

what is the function of platelets?

A
  • involved in blood clotting
111
Q

what is the reversible reaction for the transport of oxygen?

A

oxygen + haemoglobin <=> oxyhaemoglobin

112
Q

what are companion cells?

A

the active cells of the phloem, they provide energy for the phloem to transport substances

113
Q

what are guard cells?

A

cells that control the opening and closing of the stomata

114
Q

what is lignin?

A

a material that lines the xylem vessels and provides strength and support

115
Q

what are phloem?

A

a plant tissue that transports sugars from the source to the sink

116
Q

what is a potometer?

A

a piece of capillary tube that is used to investigate the rate of transpiration; water loss from the surface of the lead is measured by the distance that the air bubble travels over a certain period of time

117
Q

what are sieve tubes?

A

plant cells that have no nuclei and are connected via the cytoplasm

118
Q

what is transpiration?

A

the loss of water from the surface of the leaves by evaporation from the open stomata

119
Q

what is translocation?

A

the process of transporting sucrose around the plant

120
Q

what is water potential?

A

measure for the tendency of water to move from one area to another area

121
Q

what is water needed for in a plant?

A
  1. photosynthesis
  2. to support the cells (turgor pressure)
122
Q

what are xylem?

A

a specialised plant tissue that transports water and dissolved minerals from the roots to the leaves of the plant

123
Q

what are dissolved minerals needed for in a plant?

A

to make proteins and other molecules in leaf cells in order to grow e.g. nitrates from the soil

124
Q

what is sugar needed for in a plant?

A
  1. respiration
  2. to make other molecules i.e. cellulose
  3. to store in roots
125
Q

how do root hair cells set up a water potential gradient to get water into the root by osmosis?

A
  1. water enters the root hair cell by osmosis
  2. the root hair cell contains dissolved nutrients and minerals, giving it a low water potential
  3. these minerals have been pumped into the cells by active transport
  4. soil water has higher water potential
  5. water enters the cell by osmosis from a high water potential to a low water potential
126
Q

how are minerals taken up by the plant?

A

when the concentration of minerals in soil is lower than inside the plant, active transport is used to absorb the minerals against the concentration gradient

127
Q

what would happen if the plant relied on diffusion to absorb minerals?

A

the cells would become drained of minerals because they would travel down the concentration gradient (minerals e.g. nutrients and phosphates)

128
Q

what is the structure of xylem?

A
  • thick, cellulose wall, strengthened by lignin
  • inside of cell is hollow (xylem vessels are dead cells)
129
Q

what is the structure of phloem?

A
  • made of living cells
  • they have plasmodesmata (holes in the cell walls)
130
Q

what is the function of xylem?

A
  • transports water and minerals up the stem from the roots to the shoots and leaves
  • this transport occurs in one direction (up) only
131
Q

what is the function of phloem?

A
  • transports sugars produced in the leaves up and down the stem to growing and storage tissues, this is called translocation
132
Q

where do xylem tissues transport from/to?

A

from the roots to the shoots and leaves

133
Q

where do phloem tissues transport from/to?

A

from the leaves or storage tissue e.g. a potato to wherever respiration is taking place or to the storage organs

134
Q

what factors affect the rate of transpiration?

A
  1. temperature
  2. humidity
  3. light intensity
  4. air movement
135
Q

why does an increase in air movement increase transpiration rate?

A

because water vapour is quickly removed after diffusing out of the stomata creating a greater diffusion gradient

136
Q

why does an increase in temperature increase transpiration rate?

A

because water evaporates more quickly from leaf cells and diffuses faster

137
Q

why does an decrease in humidity increase transpiration rate?

A

because the concentration of water vapour in the air outside he leaf is low so evaporation of water and diffusion of water is fast

138
Q

why does an increase in light intensity increase transpiration rate?

A

because the rate of photosynthesis is high, needing more carbon dioxide

139
Q

how is the rate of transpiration measured?

A

using a potometer

140
Q

what is each stoma surrounded by?

A

two guard cells

141
Q

what happens to the guard cells when light intensity is high?

A

when light intensity is high, the guard cells gain water and become turgid; they curve out, opening the stomata and allowing CO2 in and oxygen and water out

142
Q

what happens to the guard cells under low light intensity or lack of water?

A

low light intensity or lack of water causes the guard cells to lose water closing the stomata

143
Q

what is the link between guard cell photosynthetic rate and transpiration?

A
  • as guard cells photosynthesise they make oxygen and glucose
  • an increase in the concentration of this in the cell causes water to move in by osmosis
  • this makes the guard cell more turgid
  • this causes the stoma to open, allowing more gas exchange

biology (7 decks)

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