Cell Biology Flashcards
1
Q
prokaryote
A
organisms that don’t contain a nucleus and lack other organelles.
simpler, smaller, eg. bacteria
2
Q
eukaryote
A
organism which contains nucleus and other organelles
complex, animal, plant
3
Q
animal cell
A
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
4
Q
plant cell
A
nucleus, cell membrane, mitochondria, ribosomes, cell wall, chloroplast, permanent vacuole
5
Q
nucleus
A
contains genetic material and is responsible for the cells activity
6
Q
cytoplasm
A
gel-like substance where most of the chemical reactions happen. It contains enzymes that these chemical reactions.
7
Q
cell membrane
A
holds cell together and controls what goes in and out.
8
Q
mitochondria
A
where most of the reactions for aerobic respiration takes place.
9
Q
ribosomes
A
where proteins are made for the cell.
10
Q
cell wall
A
it supports and strengthens the cell, also it is made of cellulose.
11
Q
permanent vacuole
A
contains sap, helps the plant stay rigid by providing it with structural support.
12
Q
chloroplast
A
where photosynthesis occurs, they contain a green substance called chlorophyll which absorbs light.
13
Q
bacterial cells
A
they are prokaryotic. contain, cell membrane, cell wall, cytoplasm. Bacterial cells don’t have a true nucleus, instead they have a single stand of DNA. May also contain plasmids.
14
Q
light microscopes
A
use light and lenses. They let us see individual cells and large subcellular structures, like nuclei.
15
Q
electron microscopes
A
use electron instead of light. Have a higher magnification. Let us see small things in more detail eg. internal structure of mitochondria. Let us see smaller things like plasmids.
16
Q
magnification formula
A
image size/ real size
17
Q
how do you calculate image size
A
magnification x real size
18
Q
how do you calculate real size
A
image size/ magnification
19
Q
difference between eukaryotic and prokaryotic cells (4 points)
A
- both have ribosomes, cytoplasm, and cell membranes, but prokaryotic cells lack other organelles
- both have cell walls, but prokaryotic cell walls are not made of cellulose
- eukaryotic contains linear organised as chromosomes found in nucleus while prokaryotic have circular loops of DNA in cytoplasm. They have extra plasmids.
- prokaryotic has flagellum and slime capsule unlike eukaryotic
20
Q
why do cells have specific structures
A
to suit their different functions
21
Q
what is differentiation
A
process where a cell changes to become specialised for its job
22
Q
what do cells develop when they change
A
different subcellular structures
23
Q
when does the most differentiation occur
A
when an organism develops
24
Q
how is differentiation different in animals compared to plants
A
in animals the ability to differentiate is lost at an early age while in plants it is never lost
25
what are the cells that differentiate in animals mostly used for and give some examples
repairing and replacing cells such as skin or blood cells
26
what are the cells that do not differentiate called
stem cells
27
give 5 examples of specialised cells
sperm cells
nerve cells
muscle cells
root hair cells
phloem and xylem cells
28
what are sperm cells specialised for
reproduction
29
what is the function of a sperm cell and how is it specialised for the function (4 points)
to get male dna to the female dna
it has a tail and streamlined head to help it swim to the egg
a lot of mitochondria to provide energy
carries enzymes to digest through the egg's cell membrane
30
what is the function of nerve cells and how are they specialised (4 points)
function of carrying electrical signals from one part of the body to the other
long to cover more distance
branched connections at the ends to connect to other nerve cells and create a network
31
what are nerve cells specialised for
rapid signalling
32
what are muscle cells specialised for
contraction
33
what is the function of muscle cells and how are they specialised for it
function to contract quickly
long so they have more space to contract
a lot of mitochondria for energy
34
what are hair root cells specialised for
absorbing water and minerals
35
how are hair root cells specialised for this
cell grows into long hairs which stick out into the soil
big surface area for absorbing water and minerals
36
what are phloem and xylem cells specialised for
transporting substances
37
what is the function of phloem cells and how are they specialised
phloem tubes transport food around plants
to form tubes cells are long and joined end to end
phloem cells have very few subcellular structures so food can flow through them
38
what is the function of xylem cells and how are they specialised for this
xylem tubes transport water around the plants -
long and joined end to end to form tubes
tubes are hollow in the centre
39
what are chromosomes and where are they found
they're coiled up lengths of dna molecules
and they're found in the nucleus
40
what do chromosomes carry
large number of genes
41
what do genes control
they control the development of characteristics such as hair colour
42
what is cell cycle
when body cells divide to produce new cells in a series of stages
43
what is mitosis
a cell division process which produces 2 identical daughter cells with the same amount of chromosome as the original cell
44
what happens during growth and replication
dna doubles
organelles replicate
cytoplasm expands
45
why does dna double during growth and replication
so when it splits there are full set of chromosomes for each two of the daughter cells
46
why do organelles replicate
so both daughter cells have necessary structures to function properly
47
why does the cytoplasm expand
to ensure there's enough material to be evenly distributed
48
what happens during mitosis after growth and replication
the chromosomes line up at the centre
chromosomes move to opposite poles
new nuclei form
and then it splits into two identical daughter cells
49
why do new nuclei form
to enclose and protect chromosomes in each daughter cell
50
name the different situations mitosis might occur in ( 6 situations)
asexual reproduction
growth and development
cancer
cell replacement
tissue repair
development of embryos
51
what is a stem cell
A stem cell is an undifferentiated cell that has the ability to develop into many different types of cells in the body
52
where are stem cells found
in early human embryos
53
where can stem cells be found in adults
bone marrow
brain
liver
fat tissue
muscle
skin
intestinal lining
54
what is different about the stem cells found in adults
they can only turn into certain cells
55
what do scientists use stem cells for
to make clones of them and then turn them into specialised cells to use in medicine or research
56
what does medicine do with adult stem cells
cure diseases
57
what is the function of stem cells in embryos
they're responsible for creating all different types of cells in the body. They can also divide and double into any type of cell
58
what is the function of stem cells in the human body
they function as a repair system by helping the body grow, repair damaged tissues and replace old, worn out cells
59
what is a meristem
parts of the plant where growth occurs
60
where in the plants are stem cells found
in meristems
61
what is the function of stem cells in meristems
stem cells continuously divide to produce more cells which can either remain in the meristems or differentiate into specialised cells such as the ones that form roots and petals
62
give an example of how stem cells can cure someone
stem cells in the bone marrow of a healthy person can replace faulty cells in another person
63
give another example of how stem cells can be used to help someone
insulin producing cells can help people with diabetes
64
give another example of how stem cells can be used to help someone
nerve cells can help people who are paralysed by spinal injuries
65
what is therapeutic cloning
In therapeutic cloning an embryo is produced with the same genes as the patient
66
how can therapeutic cloning help people
Stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment.
67
what is one reason that some people are against stem cell research
they believe that human embryos should not be used for experiments as it is a potential human life
68
how can stem cells from meristems be used
Stem cells from meristems in plants can be used to produce clones of plants quickly and economically
69
what are potential risks involved un using stem cells in medicine
stem cells grown in the lab can be contaminated with a virus which could be passed on to the patient, making them sicker
70
how else can stem cells in meristems be used
to grow more plants of rare species
71
how can farmers benefit from stem cells from meristems
can be used to grow crops of identical plants which have desired features such as disease resistance
72
what is diffusion
the spreading out of particles from an area of higher concentration to an area of lower concentration
73
how may substances move in and out of cells across the cell membrane
via diffusion
74
in what states does diffusion happen in and why
solutions and gases because particles are free to move
75
what are factors that affect of diffusion
he difference in concentrations (concentration gradient)
the temperature
the surface area of the membrane.
76
why is diffusion faster in higher temperatures
because the particles have more energy to move around faster
77
what are some molecules that can diffuse through cell membranes
oxygen, glucose, amino acids and water
78
what is the need for exchange surfaces in multicellular organisms
Not all cells are near the surface, so diffusion alone isn't enough to get oxygen or nutrients to every cell
79
what is the surface area to volume ratio of small organisms
small organisms have larger surface area compared to their volume so it easier to exchange substances directly through diffusion
80
what is the surface area to volume ratio of larger organisms
as large organisms grow their volume grows faster than their surface area which means there isn't enough surface area to supply cells with substances they need through simple diffusion
81
why is a transport system needed in multicellular organisms
because once substances are exchanged the transport system, like circulatory system, moves oxygen, nutrients and waste around the body
82
what is the effectiveness of an exchanged surface increased by (4 points)
having a large surface area
a thin membrane
having an efficient blood supply
being ventilated
83
what is osmosis
Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
84
what is a partially permeable membrane and what can and cannot pass through
membrane with small holes in it where only small molecules like water can pass through but big molecules like sucrose cannot
85
why can water molecules pass both ways through partially permeable membranes during osmosis
because they move about randomly all the time
86
what does active transport do
moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient).
87
what is meant by against a concentration gradient
movement of particles from a lower concentration to a higher concentration
88
what does active transport need in order to work
energy from respiration
89
where is a root hair cell found
on branches of roots
90
what is the function of a hair root cell
to absorb water and minerals from the soil into the plant
91
how many hair root cells do roots roughly have and what is their size
millions of them and they are microscopic
92
what does a lot of microscopic root hair cells mean for the plant
it gives the plant a large surface area for absorbing in water and minerals from the soil
93
what are the mineral ions needed for in a plant
for healthy growth
94
why can's root hair cells use diffusion to take in the mineral ions
because there is a higher concentration of minerals in the root hair cells than in the soil
95
why do humans need active transport
to stop us from starving
96
when and where is active transport needed in humans
when there is a lower concentration of nutrients in the gut but a higher concentration of nutrients in the blood
97
what is another differences between diffusion and active transport other than the concentration gradient
active transport requires energy from respiration whereas diffusion does not
98
what are exchange surfaces
areas in organisms where substances move between the inside of the body and the environment or between different parts of the body
99
what are some substances which are exchanges through exchange surfaces
oxygen and carbon dioxide
urea (waste products)
nutrients
water
mineral ions
100
what determines how easily stuff moves between an organism and the environment
the organism's surface area to volume ratio
101
how is the surface area to volume ratio in large organisms
the larger the organism the smaller the surface area compared to its volume
102
how do dissolved substances and gases diffuse into single- celled organisms and why
the diffuse directly into or out of the cell across the cell membrane because they have a large surface area compared to their volume, so enough substances can be exchanged across the membrane to supply the volume of the cell
103
how do dissolved substances and gases diffuse into multicellular organisms and why
not enough substances can diffuse from their outside surface to supply the volume of the cell so they need exchange surface for efficient diffusion.
104
how are exchange surfaces adapted to maximise effectiveness
thin membrane so substances have a short distance to diffuse
large surface area so substances diffuse at once
in animals the exchange surfaces have a lot of blood vessels so stuff can get into and out of the blood quickly
exchange surface being ventilated for gas exchange
105
what is the job of the lung
to transfer oxygen to the blood and remove waste carbon dioxide from it
106
where in the lungs does the diffusion of oxygen and carbon dioxide take place
in the alveoli
107
what is the alveoli and how many of them do the lungs have
the lung has millions of alveoli which are tiny air sacs where gas exchange takes place
108
how are the alveoli specialised to maximise the diffusion of oxygen and carbon dioxide
they have an enormous surface area
they have a moist lining for dissolving gases
they have thin walls
and have a good blood supply
109
what is the function of the small intestine
to digest food and absorb nutrients
110
what does the small intestine contain millions of
villi
111
how do villi help with absorbing the food into the blood
villi increase the surface area so digested food is absorbed much more quickly into the blood
112
what other advantageous characteristics do villi have
single layer of surface cell and a very good blood supply to assist quick absorption
113
what is the exchange surface in a leaf in which carbon dioxide diffuses in through
stomata
114
what is a stomata and where are they found
found underneath the leaf and they are tiny holes
115
what diffuses out of the stomata
water vapour and oxygen
116
what controls the size of the stomata and how
guard cells as they close the stomata if the plant is losing water
117
in other ways do the exchange surfaces maximise substance exchange
flattened shape of leaf increase area of the exchange surfaces and air spaces in the leaf increase the area of exchange substances allowing more co2 into getting into the cell
118
what is the exchange surface in fishes for oxygen and co2
gills
119
what happens as water (containing oxygen) enters through the mouth and diffuses out through the gills
oxygen diffuses from water to blood in gills and co2 diffuses from the blood into the water
120
what is each gills made out of
gill filaments
121
what are gill filaments and how do they help for exchange of gas
they are thin plates which have a big surface area
122
what are the gill filaments covered in and how do these structures provide help
covered in lamellae which increase the surface area even more
they have a lot of capillaries which speed up diffusion
have a thin surface layer of cells which minimise the distance the gas have to diffuse
123
how does the blood and water flow in the lamellae and what does it maintain
blood flows through the lamellae in one direction and water flows through the opposite and this maintains large concentration gradient between the water and the blood
124
how is the concentration of oxygen in blood compared to in water
concentration of oxygen is higher in water than in blood
125
