AQA B1 chapter 1 Cell structure and transport Flashcards

1
Q

what is resolution?

A

The ability to distinguish between two separate points in an image. A light microscope can resolve to point approx 200nm apart, but an electron microscope can resolve two points only 0.2nm apart.

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2
Q

what structures are in animal cell?

A

cell membrane, ribosomes, mitochondria, cytoplasm and a nucleus

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3
Q

what structures are in plant cell?

A

cell membrane, ribosomes, cellulose cell wall, mitochondria, cytoplasm, large permanent vacuole, chloroplasts and nucleus

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4
Q

functions of the cell membrane

A

controls what enters and leaves the cell

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5
Q

functions of the cytoplasm

A

jelly-like substance. Site of chemical reactions and contains enzymes

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6
Q

functions of the nucleus

A

contains the genetic material (DNA)

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7
Q

functions of ribosomes

A

site of protein synthesis

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8
Q

functions of mitochondria

A

site of respiration

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9
Q

functions of cellulose cell wall

A

strength and support to the plant. It is fully permeable.

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10
Q

functions of chloroplasts

A

site of photosynthesis. Contains chlorophyll (green pigment) which traps light energy.

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11
Q

functions of a large permanent vacuole

A

contains cell sap. Found in the cytoplasm.

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12
Q

how do you set up a microscope?

A

start by clipping the slide you’ve prepared onto the stage
select the lowest-powered objective lens (i.e. the one that produces the lowest magnification).
use the coarse adjustment knob to move the stage up to just below the objective lens.
look down the eyepiece use the coarse adjustment knob to move the stage downwards until the image is roughly in focus
adjust the focus with the fine adjustment knob, until you get a clear image of what’s on the slide
if you need to see the slide with greater magnification, swap to a higher-powered objective lens and refocus.

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13
Q

how to prepare a slide for a microscope

A

add a drop of water to middle of a clean slide
cut up an onion an separate it out into layers use tweezers to peel off some epidermal tissue from the bottom of one of the layers
using the tweezers, place the epidermal tissue into the water on the slide.
add a drop of iodine solution iodine solution is a stain stains are used to highlight objects in a cell by adding colour to them

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14
Q

when calculating magnification what formula should we use?

A

magnification = image size divided by actual size of specimen

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15
Q

for example an onion cell measures 5mm, it’s actual size is 0.05 micrometers. calculate its magnification

A

image size = 5 millimetres = 5000 micrometers
actual size of specimen = 0.5 micrometers
m = image size divided by actual size = 5000 divided by 5 = x1000

magnification = x1000

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16
Q

how are sperm cells adapted for their function

A

St􏰀reamlined head and long t􏰀ail 􏰀to aid sw􏰈imming
􏰇 Man􏰁y mi􏰀tochondria 􏰃􏰈(where respira􏰀tion happens􏰆) 􏰈which s􏰅uppl􏰁y t􏰀he energy􏰁 􏰀to allow􏰈 t􏰀he cell 􏰀to move
􏰇 The acrosome (􏰃􏰀top of 􏰀the head)􏰆 has digestive en􏰉􏰁zymes 􏰈which break do􏰈wn t􏰀he o􏰅uter layers of membrane of the egg cell

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17
Q

how are nerve cells adapted for their function

A

specialised to transmit electrical signals quickly from one place in the body to anot􏰀her 􏰇 The a􏰊xon is long􏰋 enabling 􏰀the imp􏰅ulses 􏰀to be carried along long dis􏰀tances
􏰇 Ha􏰄ving lo􏰀ts of e􏰊􏰀xtensions from t􏰀he cell body (called dendrites) means branched connections can form with other nerve cells
􏰇 The ner􏰄e endings hav􏰄e man􏰁y mi􏰀tochondria 􏰈which s􏰅uppl􏰁y 􏰀the energy􏰁 􏰀to make special 􏰀ransmi􏰀􏰀tter chemicals called neurotransmitters. These allow the impulse to be passed from one cell to another.

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18
Q

how are muscle cells adapted to their function

A

special pro􏰀teins 􏰃(myosin and actin) slide over each other, causing the muscle to contract 􏰇 Lot􏰀s of mi􏰀tochondria 􏰀to prom􏰄ide energ􏰁y from respirat􏰀ion for con􏰀ract􏰀ion
􏰇 The􏰁y can s􏰀tore a chemical called gl􏰁ycogen 􏰀ha􏰀 is 􏰅sed in respirat􏰀ion b􏰁y mi􏰀tochondria􏰌

19
Q

how are root hair cells adapted to their function

A

Ha􏰄ve a large s􏰅urface area d􏰅ue 􏰀to root􏰀 hairs􏰋 meaning more 􏰈wa􏰀ter can mo􏰄ve in􏰌
􏰇 The large permanent􏰀 􏰄vac􏰅uole affec􏰀ts t􏰀he speed of mo􏰄vemen􏰀t of 􏰈wa􏰀ter from 􏰀the soil t􏰀o t􏰀he cell􏰌
􏰇 Mi􏰀tochondria t􏰀o prov􏰄ide energ􏰁y from respira􏰀tion for t􏰀he act􏰀iv􏰄e 􏰀transpor􏰀t of mineral ions int􏰀o t􏰀he
root hair cell.

20
Q

how are xylem cells adapted to their function

A

upon forma􏰀tion􏰋, a chemical called lignin is deposti􏰀ed 􏰈which ca􏰅uses t􏰀he cells t􏰀o die􏰌
They become hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through
􏰇 Lignin is deposi􏰀ted in spirals 􏰈which helps 􏰀the cells 􏰈wi􏰀ths􏰀tand 􏰀the press􏰅ure from 􏰀the mo􏰄vement􏰀 of water

21
Q

how are phloem cells adapted to their function

A

Cell 􏰈walls of each cell form s􏰀ructures called sieve plates when they break down, allowing the movement of substances from cell to cell
􏰇 Despit􏰀e losing many􏰁 su􏰅b-cellular structures, the energy these cells need to be alive is supplied by the mitochondria of the companion cells.

22
Q

what is a prokaryotic cell

A

prokaryotes are simple unicellular organisms e.g. a bacterium a cell without a nucleus

23
Q

what is a eukaryotic cell

A

Eukaryotic organisms are complex multicellular organisms e.g. a human, an oak tree.

24
Q

compare prokaryotic and eukaryotic cells

A

the size of prokaryotic cells are extremely small (less than 2 micrometers in diameter) whereas eukaryotic cells are much larger cells (10 micrometers-100 micrometers)
in a prokaryotic cell there is no nucleus on the other hand in a eukaryotic cell there is a nucleus present
in a prokaryotic cell DNA is circular (only one loop of DNA) whereas in a eukaryotic DNA is linear (many chromosomes)
prokaryotic cells have few organelles but eukaryotic cells have many organelles
an example of a prokaryotic cell is an ecoli bacterium and an example of a eukaryotic cell is a human skin cell.

25
Q

what is diffusion

A

diffusion is the net movement of particles from an area of high concentration to an area of low concentration diffusion is a passive process (no energy)

26
Q

how does potassium permanganate diffuse in warm water compared to cold water

A

Potassium permanganate has diffused quicker in the warmer beaker because the particles move quicker in hotter temperatures than they do in cold temperatures.

27
Q

what can affect diffusion

A

Temperature can affect the rate of diffusion if the temperature is hotter diffusion will happen at a quicker rate.
If the diffusion distance is longer diffusion will take longer to spread out. Whereas if the diffusion is shorter it will be quicker.
States of matter will affect how fast the particles move throughout the room. Gasses diffuse more quickly than liquids, solids do not diffuse at all.

28
Q

what is osmosis

A

the movement of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane.

29
Q

explain what would happen if bag made from semipermeable membrane is tied to a glass tube and filled with a concentrated sugar solution.
This bag is placed in a less concentrated sugar solution.

A

The water molecules will move from a dilute solution (the water outside the bag) through the semipermeable membrane and moves into the concentrated solution (in the visking tube). The water then moves up the capillary tube because there is more than before. This process is called osmosis.

30
Q

describe and explain the process that takes place when a 30% sugar solution is then placed with an egg inside.

A

With the medium concentration water the egg has grown bigger there was 30% sugar. This is because the water has moved from a place of high concentration to a place a low concentration. The water has moved from the container into the semipermeable membrane. This is called osmosis. The water molecules will move from a dilute solution (the water outside the egg) through the semipermeable membrane and moves into the concentrated solution where the egg will have a lot of water inside it.

31
Q

what does it mean by lysic

A

lysic means burst

32
Q

what does it mean by crenation

A

crenation means shrivel

33
Q

describe what happens when cells are placed in distilled water compared to when they are placed in concentrated salt solution

A

when cells are placed in distilled water they swell and burst whereas when cells are placed in concentrated salt solution they shrink and shrivel

34
Q

describe and explain what happens when cells are placed in distilled water

A

the water moves from a dilute solution (inside the cell) to concentrate solution (outside the cell). The water moves through the partially-permeable into the cell and the cells swell and eventually burst (lysis).

35
Q

describe and explain what happens when cells are placed in a concentrated solution

A

the water moves from the concentrated solution (in the cell) through the partially-permeable-membrane to the dilute solution (outside the cell). The cells shrivel and shrink (crenation).

36
Q

how to investigate the effect of sugar or salt solutions on a plant tissue

A

Cut the potato into small pieces each different masses with a sharp knife.
Prepare 6 different solutions each with a different amount of sugar inside.
The 1st one will just be distilled water, 5% sugar, 10% sugar, 15% sugar, 20% sugar, 25% sugar and 30% sugar. Make sure to cut all the skin off.

Cut them into 3cm for each potato piece.
Weigh the potato pieces individually before they go in the water.
Leave them in the water for at least 40 mins (the longer the better).
After it has been in the water for at least 40 minutes take it out and measure it in grams (g) and record them individually.
Record your results in the table on the next page

37
Q

conclusion describe and explain for investigating the effect of sugar or salt solutions on plant tissue.

A

With the 50% concentration water the potato has gone down in mass. This is because the water has moved from a place of low concentration (the potato) to a place of high concentration (the water). The water has moved from the potato through the semipermeable membrane. This is called osmosis. The water molecules have moved from a concentrated solution (the potato) through the semipermeable membrane and moves into the dilute solution where the boiling tube will have more water inside it than before. With the 0% the mass increased by 4%. This is because the water has moved from a dilute solution (the water) through the semi-permeable membrane into a now concentrated solution (the potato). With the 100% sugar the mass of the potato has decreased by 14.2%. This is because the water has moved out of the potato (the dilute solution) through a semi-permeable membrane into the beaker with the water (the concentrated solution) by a process of osmosis. At 0.3 mol/dm cubed there is no net movement in and out of the cell tissue, it was at equilibrium with the water.

38
Q

what is active transport

A

the movement of substances from an area of low concentration to an area of higher concentration. Against a concentration gradient, requires ATP energy and a carrier protein in the cell membrane.

39
Q

give two examples of active transport

A

E.g. glucose is sometimes actively transported from your small intestine into the bloodstream.
E.g. mineral ions in water are actively transported from the soil into the root hair cells.

40
Q

how does a cell release energy

A

by respiration

41
Q

where in a cells does this happen

A

mitochondria

42
Q

what does more area mean in terms of active transport

A

The more area there is the more oxygen the more respiration which means energy is released which helps active transport happen more efficiently.

43
Q

how to work out surface area to volume ratio

A

find the surface area by adding up all of the faces’s areas and find the volume by multiplying the width by the length by the height
then simplify e.g. 24:8 would simplify to 3:1