b1- cell level systems (copy)

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whats a eukaryote

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1

whats a eukaryote

cells which have a nucleus (e.g. all animals and plants)

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2

whats a prokaryote

cells which dont have a nucleus (e.g. bacteria)

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3

state the 5 parts of an animal cell

  1. nucleus

  2. cytoplasm

  3. mitochondria

  4. ribosomes

  5. cell membrane

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4

what are the 3 organelles only found in plant cells

  1. cell wall

  2. permanent vacuole

  3. chloroplasts

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5

what is the nucleus

contains dna in the form of chromosomes that controls the cells activities

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6

whats the cytoplasm

gel- like substance where most of the chemical reactions take place

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7

whats the mitochondria

carry out aerobic respiration so provide energy (in form of ATP) for cells to use in chemical reactions

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8

what are ribosomes

where proteins are made in the cell (protein synthesis)

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9

whats the cell membrane

  • protective barrier around outside of cell

  • controls which substances pass in and out of the cell

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10

whats the function of the cell wall and whats it made of

  • it provides strength and support for the plant cell

  • is made of cellulose

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11

whats the permanent vacuole and what does it contain

  • it supports the cell to help keep it turgid

  • contains cell sap ( solution of sugar and salts)

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12

what are chloroplasts

  • where photosynthesis takes place so they make glucose for the cell

  • contain a green substance called chlorophyll

<ul><li><p>where photosynthesis takes place so they make glucose for the cell</p></li><li><p>contain a green substance called chlorophyll</p></li></ul>
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13

whats chlorophyll

  • green pigment within the chloroplasts which absorbs sunlight for photosynthesis

  • is chlorophyll which makes the plants green

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14

what are the 5 structures inside a prokaryotic cell

  1. chromosomal DNA

  2. plasmids

  3. ribosomes

  4. cell membrane

  5. cell wall

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15

whats chromosomal dna in prokrayotic cell

its one long circular chromosome which controls the cells activities. It floats free in the cytoplasm

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16

whats are plasmids in a prokaryotic cell

small rings of dna that arent part of the nucleoid

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17

whats magnification

how much larger a displayed image is compared with the original object

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18

whats resolution

how well a microscope can distinguish between two points that are close together

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19

whats the magnifying power of a light microscope

x 2, 000

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20

whats the magnifying power of an electron microscope

x 2,000,000

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21

what are the positives of light microscopes

  • easy to use

  • relatively cheap

  • small so easier to transport

  • produce colour images

  • can view live specimens

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22

what are the negatives of light microscopes

  • light has longer wavelength than electrons = lower resolution

  • lower maximum magnification thats not good enough to study sub cellular structures (organelles)

<ul><li><p>light has longer wavelength than electrons = lower resolution</p></li><li><p>lower maximum magnification thats<span style="color: rgb(35, 31, 32)"> not good enough to study sub cellular structures (organelles)</span></p></li></ul>
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23

what are the positives of electron microscopes

  • have a greater magnification and resolution

  • can see details within sub- cellular structures

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24

what are the negatives of electron microscopes

  • very expensive

  • hard to use - require specialist training

  • large - difficult to transport

  • black and white images

  • only view dead specimens

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25

describe the image produced by an electron microscope

the image is black and white, in 2D or 3D and has a very high magnification and resolution

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26

how has electron microscopy increased our understanding of sub cellular structures

electron microscopes can produce higher-resolution images than regular light microscopes. This allows us to see the sub cellular structures within the cell. for example they allow us to see the internal structures of mitochondria

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27

why is staining used in light microscopes

  • some specimens are colourless

  • useful to highlight different structures

  • increases contrast

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28

how do you prepare a specimen on a slide

  • pipette a drop of water onto a clean slide

  • use tweezers to place specimen on slide

  • add a drop of stain if needed

  • place a cover slip on the top and press down so there arent any air bubbles

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29

how do you view a specimen on a light microscope

  • clip your slide onto the stage

  • select lowest powered objective lens

  • focus the specimen using the coarse and fine adjustment knob

  • if you need to see your specimen with greater magnification swap to a higher powered objective lens and refocus

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30
<p>whats a on the light microscope</p>

whats a on the light microscope

eyepeice lens which you look through to see the image

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31
<p>whats B on the light microscope</p>

whats B on the light microscope

clips which hold the slides in place

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32
<p>whats C on the light microscope</p>

whats C on the light microscope

coarse adjustment knob

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33
<p>whats D on the light microscope</p>

whats D on the light microscope

fine adjustment knob

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34
<p>whats E on the light microscope</p>

whats E on the light microscope

high and low power objective lenses which magnify the images

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35
<p>whats F on the light microscope</p>

whats F on the light microscope

stage which supports the slide

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36
<p>whats G on the light microscope</p>

whats G on the light microscope

lamp which shines light through slide so images can be seen more clearly

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37

how do you calculate the total magnification

total magnification = eyepiece magnification x objective lens magnification

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38

whats the formula to calculate magnification from image size and actual size

image size = actual size x magnification

(I AM formula)

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39

whats the structure of dna

is a polymer made up of two strands wrapped around each other to form a double helix

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40

whats a polymer

large, complex molecules composed of long chains of monomers joined together

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41

what are chromosomes

long molecules of coiled up dna which is divided into short sections called genes

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42

whats a gene

a small section of DNA on a chromosome

each gene codes for a particular sequence of amino acids to make a specific protein

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43

what does a nucleotide contain

a sugar, phosphate group and a base. The base is attached to the sugar

<p>a sugar, phosphate group and a base. The base is attached to the sugar</p>
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44

what are the 4 different bases in DNA and how do they pair up

a→t

c→ g

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45

what are enzymes

biological catalysts that speed up the rate of metabolic reactions

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46

what are catalyists

a substance that increases the speed of a chemical reaction without being used up in the process

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47

whats the structure of enzymes

enzymes are proteins that contain an active sight that fits into a specific substrate

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48

what do we call the complex that if formed when an enzyme binds to a substrate

enzyme substrate complex

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49

when were discussing enzymes, what does complimentary mean

s substrate must be complementary to fit the active sight of the enzyme. This means it ‘fits’ the active sight.

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50

what is the special region of the enzyme that binds to the substrate

active sight

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51

whats the lock and key hypothesis for enzyme action

  • is a model that explains how enzymes are specific for their substrate.

  • It states that an enzyme is specific for its substrate like a key is for its lock.

  • substrate has to exactly match the shape of the enzymes active sight for a reaction to be catalysed

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52

what are the 4 factors that affects enzyme function

  1. temperature

  2. pH

  3. substrate concentration

  4. enzyme concentration

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53

how does changing the temperature affect an enzyme controlled reaction

  • a higher temperature increases the rate at first as the enzyme and substrate move around more so are more likely to meet up and react

  • but if it gets too hot the bonds holding the enzyme together start to break

  • the active sight starts to change shape

  • if it changes shape enough, the enzyme wont be able to bind to the substrate - at this point its been denatured

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54

whats an enzymes optimum temperature

the temperature that gives the highest enzyme activity

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55

whats the effect of the pH on an enzyme

  • if the pH is too high or low it interferes with the bonds holding the enzyme together which start to change the shape of the active sight (substrate can still fit but less well)

  • active shape changes so much that the substrate cant fit - denatured

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56

whats an enzymes optimum pH

the pH the enzymes work best at

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57

whats the effect of enzyme concentration on the rate of the reaction

  • the more enzyme molecules there are in a solution, the more likely a substrate molecule will meet up with it so the rate of reaction increases

  • if the amount of substrate is limited theres a point when all the substrates are dealt with so adding more enzyme has no further affect

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58

whats the effect of substrate concentration on the rate of reaction

  • the higher the substrate concentration the more likely the enzyme will meet up and react with the substrate

  • however once all the active sights are full, adding more substrates makes no difference

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59

whats cellular respiration

a universal chemical process that occurs in all living cells that breaks down glucose to release ATP, which may be used as energy to power many reactions throughout the body.

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60

whats ATP

it stores the energy needed for many cell processes

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61

what type of reaction is respiration

exothermic as cellular respiration is just releasing the energy from the glucose

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62

give 3 examples of how cells use the energy from respiration

  • Chemical reactions to build larger molecules from smaller molecules

  • Muscle contraction to allow movement

  • Keeping warm (to maintain a constant temperature suitable for enzyme activity)

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63

what are the 2 types of respiration

  1. aerobic respiration

  2. anaerobic respiration

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64

whats aerobic respiration

  • the chemical reaction in cells that uses oxygen to break down nutrient molecules to release energy

  • complete breakdown of glucose to release a relatively large amount of energy for use in cell processes and reactions

  • Carbon dioxide and water are produced as waste products as well as releasing useful cellular energy

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65

how much ATP does aerobic respiration produce

32 ATP

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66

whats the word equation for aerobic respiration

glucose + oxygen → carbon dioxide + water

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67

whats the chemical equation for aerobic respiration

C6H12O6 + 6O2 + 6H2O → 6CO2 + 6H2O (opposite of photosynthesis)

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68

whats anaerobic respiration

  • chemical reaction in cells that breaks down nutrient molecules to release energy without using oxygen

  • releases much less energy than aerobic respiration as it involves the incomplete breakdown of glucose

  • Different breakdown products are formed depending if the process is happening in animals or plants/fungi

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69

how much ATP does anaerobic respiration produce

2ATP

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70

where does anaerobic respiration take place in animals

  • muscle cells during vigorous exercise

  • When individuals exercise at high intensities, their muscles have a higher demand for energy

  • Bodies can only deliver so much oxygen to muscle cells for aerobic respiration

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71

whats the word equatiopn for anerobic respiration in animals

glucose → lactic acid

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72

when do plants need to use anaerobic respiration

  • if plants are in waterlogged soil, there is little or no oxygen available

  • The plant root cells will respire anaerobically

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73

whats the word equation for anaerobic respiration in plants

glucose →ethanol + carbon dioxide

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74

whats fermentation

  • Anaerobic respiration in yeast

  • is economically important in the manufacture of bread (where the carbon dioxide produced helps the dough to rise) and in brewing (where the ethanol produced makes beer)

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75

what is oxygen debt

the extra oxygen that is needed to break down the lactic acid formed in anaerobic respiration

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76

what are biological molecules

molecules found in living organisms and are produced by cells

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77

what are nutrients

substances needed for growth, repair and metabolism

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78

what type of molecules are carbohydrates and proteins

polymers

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79

what are carbohydrates made up from

  • simple sugars e.g. glucose which are joined in long chains (polymers)to make complex carbohydrates e.g. starch

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80

use the terms polymer and monomer to explain the difference between simple sugars and complex carbohydrates

  • complex carbohydrates are large molecules made up of lots of individual smaller molecules called simple sugars

  • complex carbohydrates are polymers whilst simple sugars are monomers

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81

how are carbohydrates broken down

the polymer molecules are broken down back into sugars when the chemical bonds between the monomers are broken

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82

what type of enzyme breaks down carbohydrates and where are they found

carbohydrases - found in mouth and small intestine

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83

what are the monomers that make up protein

amino acids

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84

what enzyme breaks down protein back into amino acids and where are they found

Protease - found in stomach and small inestine

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85

what are lipids made up of

fatty acids and glycerol

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86

true of false , lipids are polymers

FALSE - they are not polymers because they dont form a long chain of repeating units

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87

what enzyme breaks down lipids and where are they found

lipase - found in small intestine

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88

what are photosynthetic organisms

the main producers of food and therefore biomass for life on Earth

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89

what type of reaction is photosynthesis

endothermic - energy is transferred from the environment during it

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90

whats the purpose of photosynthesis

for photosynthetic organisms (e.g. green plants and algae) use energy from the sun to make glucose

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91

whats the word equation for photosynthesis

carbon dioxide + water → glucose + oxygen

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92

whats the chemical equation for photosynthesis

6CO2 + 6H2O → C6H12O6 + 6O2

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93

where does photosynthesis take place

in the chloroplasts

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94

whats the process of phtosynthesis

  1. energy transferred by light is used to split water into oxygen gas and hydrogen ions

  2. carbon dioxide gas then combines with hydrogen ions to make glucose

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95

whats the experiment to calculate the rate of photosynthesis

  • pond weed is places in a test tube full of water

  • the top is sealed with bung

  • a lamp is placed at a measured distance from the test tube

  • count the number of oxygen bubbles coming out of the cut stem in 1 minute

  • repeat experiment and record results

  • calculate average number of bubbles produced per minute

<ul><li><p>pond weed is places in a test tube full of water </p></li><li><p>the top is sealed with  bung</p></li><li><p>a lamp is placed at a measured distance from the test tube</p></li><li><p>count the number of oxygen bubbles coming out of the cut stem in 1 minute</p></li><li><p>repeat experiment and record results</p></li><li><p>calculate average number of bubbles produced per minute</p></li></ul>
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96

whats the effect of temperature on photosynthesis

  • with an increase in temperature, the rate of photosynthesis also increases

  • because reaction is controlled by enzymes, this only continues up till a certain temperature and then the enzymes will denature and the rate of reaction will decrease

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97

whats the effect of light intensity on photosynthesis

the higher the light intensity, the rate of photosynthesis increases

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98

how is the relationship between the light source and the plant inversely proportional

because as the distance between the light source and the plant increases, the light intensity decreases

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99

whats the effect of carbon dioxide concentration on photosynthesis

as carbon dioxide concentration increases, so does the rate of the reaction

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100

what are the limiting factors in photosynthesis

  • carbon dioxide, light intensity and temoerature

  • in low levels these restrict any increase in the rate of photosynthesis

  • despite increases in other factors the rate of photosynthesis will not increase any more

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