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Biology > B1- Cell Structure and organisation > Flashcards

B1- Cell Structure and organisation Flashcards

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1
Q

Why are microscopes useful ?

A

-They provide magnification to observe cell strctures , see things human eye cant see.
-Enabless study of small and organsims diseases - so increases our understadning of cells and subceullar structures..

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2
Q

What do microscopes allow us to do ?

A

-Microscopes allow us to magnify .

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3
Q

What is the meaning of resolution?

A

The ability to distinguish between two sepearte points (clarity).

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4
Q

How do light microscopes work ?
Their advanatages

A

Light microscopes use a beam of light to form an object . Mangify several thousand times .
-ADV - releatively cheap
-Can be used anywhere
-Can be used to magnify live specimens .

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5
Q

Disadvanatges of light microscopes (1) .

A

Light microscopes have limited magnification (can’t view structure inside nucleus easily) as magnification is not powerful enough .

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6
Q

Disadvanagtage of light miroscopes (2)

A

Ligh microscopes have a limited resolution (images blurred even if you wer eto increase the magnification , can’t see fie detail).

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7
Q

Scientists realised if they wanted to view structures in detail , need an electron microscope .

A

.

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8
Q

How does an electron microscope work ?
What are its advanatges ?

A

-Elecron microscopes use a beam of electrons to form images . Magnify objects up to around two million times
-They have a much greater magnification and resolution than light microscopes .

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9
Q

Disadvanatage of electron microscopes .

A

-Have to be large and are expensive .
-Have to kept in special temepatrue , pressure and humdiity controlled rooms .

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10
Q

How do you calculae magnification ?

A

Magnfiication =size of image /size of real object .
i over m*o

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11
Q

Magnficiation equation triangle .

A

size of image / magnification*size of real obejct .

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12
Q

do quesiton on sheet .

A

.

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13
Q

Animals are eukaryotes , explain .

A

-Their Genetic maerial (DNA) is enclosed in a nucleus .

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14
Q

What are the structures in An animal cell ?

A

-Cell membrane
-Ribosomes
-Mitochondira
-Cytoplasm
-Nucleus .

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15
Q

What is the function of the nucleus ?

A

-Encloses the genetic material which controlls cells activity

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16
Q

Inside the cell is the cytoplasm , what is its function ?

A

-The cytoplasm is a water solution where chemical reactions take place (first stage of respiration )

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17
Q

The whole cell is enclosed in a cell membrane , what is its function ?

A

-The cell membrane controls the molecules that can enter and leave the cell .

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18
Q

What is the Mitochondria ?

A

-Where aerobic respiration takes place .

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19
Q

What are Ribosomes ?

A

-Very small so is mitochondira but ribosomes can be only seen with an electron microcosope.
-Site of protein synthesis .

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20
Q

Draw an animal cell .

A

.

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21
Q

What are the strcutures in a plant cell ?

A

-cytoplasm
-Nucleus
-Cellmemrbane
-Cell wall
-Mitochondira
-Ribiosomes
-Chloroplast
-Vacuole

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22
Q

What structures do plants and animals both have in common

A

nucleus-
ribiosome
-mitochondria
-cell memrbane
*cyoplasm

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23
Q

Three structures only plants have ?

A

-Cell wall
-Vacuole
-Chloroplasts

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24
Q

-What are chloroplasts ?

A

Green structures that contain chlorophyll - are the sites of photosynthesis .

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25
Q

-What are cell walls ?

A

-Mde from cellulose , stengthens the cell .

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26
Q

-What are vacuoles ?

A

-Vacuoles are filled with a fluid called cell sap . Vacuole hellps to give the plant its shape .

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27
Q

Draw a plant cell .

A

.

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28
Q

Meaning of a eukaryotic cell .

A

Eukarytoic cells contin their genetic materual (DNA) enclosed in a nucleus .

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29
Q

Example of eukaryotic cells .

A

Plants and animals.

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30
Q

Meaning of a prokaryotic cell

A

In prokaryoitc cells , the genetic material (DNA) is not enclosed in a nucleus .
-Prokarytoic cells are much smaller than eukaryotic cells .

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31
Q

Example of a prokaryotic cells and its characteristics .

A

-Bacteria
-Don’t have a nucleus so genetic material consists of a single loop of DNA .
-Or small rings of DNA known as Plasmids .

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32
Q

What functions do prokaryotic cells have .

A

Example bacteria
Genetic material loops
cytoplasm
cell membrane
slime capsule - bacteria have this to move and disguise in the white blood cells .
cell wall
plasmids-extra dna code for antibitoic resistance .
flagella- a long protein trand helps to move about cell .

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33
Q

Most animal cells are specialised , what does this mean ?

A

They have adaptations which help yhrm yo carry out a particular function .

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34
Q

When cells become specialised , what do scienitsts call them ?

A

differentation .

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35
Q

Three specialsied cells you need to know about .

A

-Sperm cells
-Nerve Cells
-Muscle cells

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36
Q

What is the job of a sperm cell ?

A

-The job of a sperm cell is to join with an ovum (egg cell) , We call this process fertilisation .
-During fertiisation , the genetic information of the voum and sperm combine ,

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37
Q

sperm cells contain their geentic information in the nucleus , sperm contint only half the genetic info of adult cells .

A

.

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38
Q

Give one adaptaiton of a sperm cell .

A

Sperm cells have a long tail , which allows them to swim to the ovum . They are also streamlined , making this easier .

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39
Q

Give another adaptation of a sperm cell .

A

Sperm cells are packed full of mitochodri a , these provide the energy needed for swimming .

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40
Q

Give the last adaptation of a sperm cell .

A

Sperm cells containe enzymes which allow them to digest their way thorugh the outer layer of the ovaries .

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41
Q

What is the job of a nerve cell ?

A

The job of a nerve cell is to send electrical impulses around the body .

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42
Q

Give one adaptation of the nerve cell .

A

The nerve cell has a long axon , the axon carries electrical impulses from one part of the body to another .

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43
Q

Give another adaptation of the nerve cell .

A

The axon is covered in mgelin . Mgelin insualtes the axon and speeds up the transmission of the nerve impulse .

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44
Q

Give anotherr adaptation of the nerve cell .

A

The end of the axon has synapses . Synapses are junction which allow the impluse to pass from one nerve to another .

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45
Q

Give the final adaptation of a nerve cell .

A

The cell body of the enrve cell containts dendrites , these increase the surface area so that the nerve cells can connect more easily .

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46
Q

Draw a nerve cell with all adaptations.

A

question asked is how is nerve , muscle and sperm cell specialised .

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47
Q

What can a muscle cell do ?

A

Muscle cells can contract (get shoretr) .

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48
Q

How do muscle cells contract

A

To do this muscle cells contain protein fibres , which can change their length .

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49
Q

Give one adaptation of a muscle cell.

A

When a msucle cell contracts , these protein fibres shorten , decreasing the length of the cell .

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50
Q

Give another adaptation of a muscle cell .

A

Muscle cells are packed with mitochondria , to provide energy for muscle contraction .
-Muscle cells work together to form muscle tissue .

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51
Q

Give one adaptation of root hair cells .

A

Root hair cells have hairs , these increase the surface area of the root , so it can absorb water and dissolved minerals more effectively .

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52
Q

Root hair cells do not contain chloroplasts as they are underground .

A

.

53
Q

Draw a root hair cell .

A

need a root hair
cell wall
nucleus
vacuole .

54
Q

Where are xylem cells found ?

A

Xylem cells are found in the plant stem .

55
Q

What do xylem cells do ?

A
  • They form long tubes .
    -These long tubes carry water and dissolved minerals from the roots to the leaves .
56
Q

Give one adaptation of a xylem cell .

A

Xylem cells have very thick walls containign ligngin .
-This provides support to the plant .
-However as the cell wass are sealed with lignign this scauses zyelm cells to die .

57
Q

Give another adaptation of xyelm cells .

A

-So xylem cells don’t die , the end walls between cells have broken down . This means that the cells now form a long tube so water and dissolved minerals can flow easily .

58
Q

Give the final adaptaion of xylem cells .

A

Xylem cells contain no nucleus , vacuole cytoplasm or cholorplast , hey have no intenral structure , making it easier for water and minerals to flow .

59
Q

What do pholem cells do ?

A

Phloem tubes carry dissolved sugars up and down the plant .

60
Q

Phloem containts phloem vessels what are they ?

A

Phloem vessel cell - thse have no nucleus and are limited to cytoplasm ,

61
Q

Phloem conyaints two types of cceells what are they

A

pores and sieve plaates .
-The end walls of the vessels have pores called sieve plates . Both these features allow dissolved sugars to move through the cell interior .

62
Q

Whhat is a companion cell , how does it work ?

A

Phloem
-Due to limited cytoplasm and mitochondria , each phloem vessel has a companion cell connected by pores .
-Mitochondira in the companion cells , provide energy to the phloem vessel cells .

63
Q

Where can diffusion take place ?

A

Through the cell membrAane .
-One way molecules move in out of the cell is diffusion .

64
Q

What is the meaning of diffusion ?

A

Diffusion is the spreading out of particles resulting in an overal movement from an area of high concentration to an area of low concentraition .

65
Q

Why do cells need oxygen ?

A

Cells need oxygen for respiration which is carried out in the mitochondria .

66
Q

Diffusion of oxygen into cells .

A

-Cells are surrounded by a high concentration of oxyegn
-. Oxygen is transported in the bloodstream from the lungs .
-Oxygen moves into the cell from a area of high concentration to an area of low concentration .
-The waste of product of oxygen is a waste gas Carondixodie .

67
Q

Diffusion of carbondioxide .

A

-As carbondioxide is a waste porduc of oxygen , we have a higher concentration of carbondioxide inside cells than outisde .
-So carbondioxide moves out th cell by diffusion .

68
Q

How does urea diffuse out of the cell ?

A

-Urea is a waste produc produced by cells .
-I diffuses out of the cells into the blood plasma and is excreeted by the kidneys .

69
Q

Where can diffusion take place ?

A

Through the cell membrAane .
-One way molecules move in out of the cell is diffusion .

70
Q

What is the meaning of diffusion ?

A

Diffusion is the spreading out of particles resulting in an overal movement from an area of high concentration to an area of low concentraition .

71
Q

What is another factor that effects diffusion ?

A

Temperature : The higher the temperature , the greater the rate of diffusio. As the paricles have more kinetic energy and are moving faster .

72
Q

Diffusion of oxygen into cells .

A

-Cells are surrounded by a high concentration of oxyegn
-. Oxygen is transported in the bloodstream from the lungs .
-Oxygen moves into the cell from a area of high concentration to an area of low concentration .
-The waste of product of oxygen is a waste gas Carondixodie .

73
Q

Diffusion of carbondioxide .

A

-As carbondioxide is a waste porduc of oxygen , we have a higher concentration of carbondioxide inside cells than outisde .
-So carbondioxide moves out th cell by diffusion .

74
Q

How does urea diffuse out of the cell ?

A

-Urea is a waste produc produced by cells .
-It diffuses out of the cells into the blood plasma and is excreeted by the kidneys .

75
Q

What is one factor that effects the rate of diffusion ?

A

-Difference in concentration - known as concenrtation gradient .
-The greater the concentration gradient , the faster the diffusion that takes place .

76
Q

If the concentration gradient is smaller …

A

The diffusion will be slower .

77
Q

What is the final factor that effects diffusion ?

A

Surface area of membrane . The larger the surface area of the cell membrane , the greater the rate of diffusion .

78
Q

What is osmosis ?

A

Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane .

79
Q

What is a dilute solution ?

A

A dilute solution contains a high concentration of water .

80
Q

What is a concentrated solution ?

A

A concentrated soulution contains a low concentration of water .

81
Q

What is a partially permeable membrane ?

A

It allows some molecules to pss through but not all molecules .

82
Q

What are the water concentrations in the cytoplasm ?

A

The cytoplasm of cells is a relatively concentrated solution . Contins relatively low concentrations of water .

83
Q

What will happen if an animla cell was put into water ?

A

Osmosis will take place and water from outside the cell will come inside . This will cause the cell to expand even burst .

84
Q

What will happen if we put an animal cell in a very concentrated solution ?

A

-If we put an animal cell in a very concentrated solution , the water will move out the cell by osmosis and the cell will shrink .

85
Q

What will happen if we place a plant cell into water ?

A

-The water will move into the cell by osmosis and the cell will expand .

86
Q

What prevents the plant cell from bursting in osmsosis .

A

In low concenrations , plant cell expands ,
-The cell wall prevents the plant cell from bursting . Instead the cell wall becomes swollen . Scientists call this TURGID .

87
Q

What will happen if we put a plant cell into a concentrated solution ?

A

-Water moves OUT of the plant cell by osmosis , causing the cell to shink , scientists say the cell has become flaccid .

88
Q

What is the first stage of the osmosis RP ?

A

-First we peel the potato . That is because the potato skin can affect osmosis .

89
Q

What is the second stage of the osmosis RP ?

A

Use a cork borer to produce three cylinders of potato ..
-Uising a cork borer makes all the cyliinders the same diameter .

90
Q

What is the third stage of the osmosis RP ?

A

-Use a scalpel to trim the cylinders to the same lengh . (around 3cm)
-Any shorter lengths may not be able to measure the efect of osmosis .

91
Q

What is the fourth stage of the osmosis RP ?

A

-Measure the length of each cylinder using a ruler and the mass of each cylidner using a blance .

92
Q

What is the fifth stage of the osmosis RP ?

A

Now place each cylidner into a test tiube . Add cmcubed of a 0.5 molar sugar solution to the first test tube .

93
Q

What is the sixth stage of the osmosis RP ?

A

We then add 10 cm cubed of 0.25 sugar solution into the second test tube and 10 cm cubed of disitlled water to the third test tbe .

94
Q

Why do we use distilled water ?

A

-We use distilled wayer , as it contains no dissolved substances that could effect the rate of osmosis .

95
Q

What is the seventh stage of the osmosis RP ?

A

-Now leave the potato cylidners overnight to alllow osmosis to take place .

96
Q

What is the eigth stage of the osmosis RP ?

A

-Next remove the potato cylidners gently and roll them on a paper towl to remove ay surface mositure .
(Don’t press ahrd , don’t wanna remove any water out of the cells ).

97
Q

What is the ninth stage of the osmosis RP ?

A

-Measure the length and mass of the cylidners again

98
Q

-Now we need to calculate the percentage change , how do we do that ?

A

Percentage change = change in value / the oirginal value times byb 100

99
Q

Using the percentage change now a plot a graph .

A

-Mass change on the y axis
-Concenration of sugar solution on the x axis . .

100
Q

On the sheet , what does the top of the graph show ?

A

-In water , the potato cylidner gains mass , as ater moves into it by osmosis .

101
Q

On the sheet , what does the bottom of the graph show ?

A

In concentrated sugar solution , the cylinder looses mass as water moves out by osmossis .

102
Q

On the graph , what happens where the line crosses the x axis ?

A

-There is no change in mass of concentration of sugar solution .

103
Q

-Why is there no change in mass of concenration when crossing x axis ?

A

-That is because the concentration outisde the same cell is the same as the concentration inside . So no overall osmosis takes place .

104
Q

Carrying on from that point , where i the approximate concentration insdie the cell ?

A

-The approximate concentration inside the cell is where the line crosses the x axis .

105
Q

What if a cell needs to bring in a molecule , that is already at a high concentration insdie the cell ?

A

Use active transport .

106
Q

What is active transport ?

A

Moves substances from a more dilute solution to a more concentrated solution (against the concentration gradient )

107
Q

What does active transport require ?

A

Energy fromrr espiration .

108
Q

What is the difference between active transport and diffusion ?

A

-Active transport , particles move against the concentraton gradient (diffusion moves doen the concentration gradient)
-Active transport requires energy from respiration (diffusion does not ).

109
Q

Give example of acitve transport in humans .

A

-Cvity of small intestine , where food is difesed , can find molecules produced when food digested like sugar .

110
Q

Give example of acitve transport in humans . (2)

A

-The concentration of sugars in the lumen is lower thn the sugars inside cells . So can’t diffuse in , insetad sugars are carried in by active transport .

111
Q

Give example of acitve transport in humans .(3)

A

-Once transported into cell , sugars can be transported into blood and carried around the body .
-These cells have lots of mitochondria -to carry out respiration , providing energy needed for active transport .

112
Q

Give an example of active transport in plants .

A

-Root hair cells foud in plants .
-Root hair cells transport ionsl ike mgensium into the plant from soil , needed to make chlorophyl in the leaves .

113
Q

Give an example of active transport in plants .(2)

A

The cocnentration of ions in the soil is lower than the concentration insidie the root hair cell . Active transport moves ions into the cell .

114
Q

Give an example of active transport in plants . (3)

A

-These ions can then be tranpsorted into xylem vessels and moved to the leaf .
-Root hair cells have a lot of mitochondria -providing energy for active transport .

115
Q

Having huge surafce area for its volume is known as what ?

A

surface area :volume ratio

116
Q

How to work out
surface area of a side ?
total surface area ?
and volume ?

A

LW
LWnumber of sides
LW*H
surface area to volume ratio =t otal surface area : volume .

117
Q

-As organsims get larger …
why is this a problem ?

A

… the surface area : volume ratioo falls sharply .
Huge problem for multiceullar organsims as their surface area is not large enough for their volue .

118
Q

.

A

-Cells on the surface can get enoguh oxygen simply by diffusion .
-However , not enoguh oxyegn can difuse into the cells int he center of the organism .
-They are too far away from the surface .

119
Q

Animals have solved this problem how ?

A

-Special structures foer as exchange with high surface area , lungs .
-Animals have a transport system that carry gases around body .

120
Q

How do fishes breathe ?

A

-Get oxyegn from water .
-The oxygen rich water passes into the mouth . It then flows over the gills , where oxygen is transported into the bloodstream .

121
Q

How do fishes breahe ? (2)

A

-The gills are covered ina very large number of fine filaments .
-This is where gasses pass in and out of the blood .

122
Q

How do fishes breathe (3)

A

-Deoxygenated blood passes into the filament . Oxgen diffuses from the water into the blood .
-Oxygenated blood returns to the body .

123
Q

Give one adaption of filaments to increase rate of diffusion .

A

Filaments give gills a massive surface area .

124
Q

Give another adaption of filaments to increase rate of diffusion .

A

Filamnets also have a thin membrane , to provide a short diffusion pathway .

125
Q

Give the fnal adaption of filaments to increase rate of diffusion .

A

The filaments have an efficent blood supply , to take the oxygenated blood away . This ensures the concentrtion gradient is always high .
-All these adaotations make diffusion as efficent as possible .

126
Q

How to use a microscope s1

A

-Choose an objective lens with the lowest magnification .
-Put the slide on the stage of the microscope .

127
Q

How to use a microscope s2

A

-Usinging the coarse focusing wheel m oisutuib tge sanoke as close to the lens as possible .

128
Q

How to use a microscope s3

A

Whilst looking throught the eye peicce , use the coarse focusing wheel to m ove the sample into focus .

129
Q

How to use a microscope s4

A

-Change it to the next magnification .
-Use the fine focus only to fucs the image .

Biology (25 decks)

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