I gcse biology

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excretion

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Biology

358 Terms

1

excretion

removal of the waste products of metabolism, toxic materials, and substances in excess of requirements

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2

respiration

breakdown of glucose inside cells to give energy

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3

all living things (mrs gren)

Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition

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4

animal cell differences

no cell wall, no chloroplasts, no vacuole, glycogen food storage

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5

plant cell differences

cell wall, chloroplasts, vacuole, starch food storage

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6

animal cell has

semi permeable cell membrane, cytoplasm, glycogen food store, nucleus

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7

plant cell has

permeable cell wall (glucose fibre), nucleus, cytoplasm, vacuole filled with liquid, chloroplasts (only in green plants), cell membrane, starch grain food storage

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8

animal and plant cells are _______ for the jobs they do

specialized

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9

magnification

size of drawing (mm)/actual size

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10

when you increase the size of something, the surface area

does not increase relative

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11

the bigger an object becomes, the _surface it has _

less, relative to its volume

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12

no matter the size of the solid, the substance will _. That is why cells are _, so that the _that is diffusing into them can be _.

diffuse at the same rate, so small, oxygen,evenly spread/distributed into the whole cell easily.

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13

as you get a _______ organism/cell, diffusion is made _______

larger, harder/takes longer

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14

cells and multicellular structures have _______ to increase _______ to maximize _. For example, _.

specialized structures, surface area, rate of diffusion. Fish gills, leaf is not thick.

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15

osmosis

diffusion of water through a SEMI PERMEABLE MEMBRANE. Osmosis takes place from an area of low solute concentration to high solute concentration (high water potential --> low water potential)

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16

water potential

The ability of the water to move. There is more water leaving high water potential areas.

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17

the water will tend to move until

there are the same number of molecules on both sides.

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18

hypotonic

lower solute concentration

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19

hypertonic

higher solute concentration

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20

isotonic

equal solute concentration

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21

animal cell add to water (ex. red blood cell)

water moves in, cell swells and eventually bursts

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22

animal cell add to strong sucrose solution (ex. red blood cell)

water moves out, cell shrinks, cell deflates, crinkles

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23

plant cell add to water

water moves in, cell swells, cell turgid (full of water). cell will not burst as the cell wall is quite strong

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24

plant cell add to strong sucrose solution

water moves out, vacuole + cytoplasm shrink, cytoplasm comes away from the cell wall. Cell is plasmolysed. Cell wall remains the same/

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25

Plasmolysed plant cell

The cell has lost water and the cytoplasm has shrunk; the membrane has pulled away from the cell wall

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26

when drawing a graph

pay attention to scale on the axis!!! Independent variable on the x axis, dependent variable on the y axis.

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27

autotrophs

organisms that make/produce their own food (like plants)

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28

heterotrophs

organisms that need to eat food (like humans)

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29

fibre is found in

the cell wall

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30

lipids are found in

cell membrane

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31

fats vs oils

fats - found in animals, solid at room temp. oils - found in plants, liquid at room temp.

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32

Monomers

small unit that can join together with other small units to form polymers (larger substances)

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33

Carbohydrates are made of

monosaccharides

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34

proteins are made of

amino acids

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35

main food chemicals are

carbohydrates, proteins, lipids, minerals, vitamins, fibre, water

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36

carbohydrates

provide energy

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37

simple carbohydrates

eg. glucose - sweet and soluble, provide immediate energy

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38

complex carbohydrates

polymers/polysaccharides made from simple sugars. Used as energy store - eg starch, glycogen.

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39

Examples of simple carbohydrates

fruit, vegetables, sugars, milk

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40

Examples of complex carbohydrates

whole wheat bread, pasta, rice, oats, potatoes

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41

lipids

long term energy storage (2x as much as carbs). Used as insulators, used in cell membranes, water proofing (like waxy leaves)

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42

examples of foods containing lipids

margarine, fried food (churros, chips, fries)

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43

proteins

made of long chains of amino acids, used for bodybuilding and repair

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44

there are _______ amino acids. _______ are essential and must be eaten. The rest can be _______.

20, 8, made by the body

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45

examples of proteins

meat and beans

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46

vitamins and minerals

needed in very small amounts, but are essential.

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47

examples of minerals

iron, zinc, calcium, etc.

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48

examples of vitamins

K, B, E, B12, etc.

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49

malnourished

Having a diet that lacks the correct balance; too much or too little of one thing

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50

turgor pressure

The pressure that water molecules exert against the cell wall

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51

Chemical elements that make up carbohydrates, fats, and proteins

oxygen, carbon, hydrogen, (protein: nitrogen too)

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52

starch and glycogen made of

glucose

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53

fats and oils are made of

fatty acids and glycerol

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54

test for starch

add iodine, positive test turns black

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55

test for reducing sugar

add benedict's solution, boil, positive test turns dark orange

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56

test for protein

add biuret solution, positive test turns purple

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57

test for fats and oils

add equal parts ethanol and water, shake well, positive test turns cloudy/white

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58

water is

important as a solvent

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59

Enzymes are a type of ______ called ______ because they are made by _. They are a type of _.

catalyst, biological catalysts, living organisms, protein molecule.

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60

substrate

(enzyme specific) something that reacts to make a product

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61

The enzyme has a ______ so that a ______ can fit and carry out its reaction. Each enzyme is specific for one job and can only do ______.

specific shape, specific substrate, one thing

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62

active site

The part of an enzyme where the chemical reaction occurs. Specific to the substrate it catalyses.

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63

How does an enzyme reaction work?

The substrate fits into the active site of the enzyme. The enzyme causes chemical change in the substrate.

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64

Why, up to a certain point, does increasing the temperature of an enzyme increase the rate of reaction?

the molecules and enzymes increase KE and move around more and faster meaning they are more likely to bump into each other

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65

Why does too hot a temperature cause the rate of reaction to slow and eventually an enzyme to denature?

because it causes the active site to change in shape slightly so it takes longer for the substrate to fit. Eventually, the substrate no longer fits.

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66

optimum temperature

The temperature at which an enzyme is most active

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67

denatured enzyme

An enzyme which no longer functions

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68

effect of cold temperatures on enzymes

Cold temperatures decrease the rate of reaction because molecules are moving slower and are less likely to collide, but cold temperatures do not denature the enzyme, so if the temperature is brought back up, the chemical reaction will speed back up to a normal process.

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69

Effect of pH on enzyme activity

All enzymes work best at optimal pH. above and below the optimal pH the rate of reaction decreases. Extreme pH changes can denature the enzyme.

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70

balanced diet

contains all the nutrients in the right amounts that the body needs (carbohydrates, protein, fats, vitamins + minerals, and fibre)

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71

Vitamin C

from citrus, deficiency scurvy(gums bleed, swollen, tired), helps with repair of body tissue/immune system

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72

Vitamin D

from sunlight/fish oil/red meat, deficiency rickets (leg bones weak and bent), helps with bones and teeth

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73

Iron

from red meat/pulses (lentils, beans, etc.), deficiency anemia (not enough O2 - tired, dizzy) carries O2, needed for hemoglobin

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74

Calcium

from dairy/bones of fish like sardines, deficiency bones and teeth go brittle, helps with bones and teeth

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75

Malnutrition is caused by

unbalanced diet

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76

Kwashiorkor

protein deficiency

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77

Marasmus

lack of energy

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78

digestion

breakdown of large insoluble molecules (eg. protein, starch) into small molecules (eg. glucose, simple sugars) which can be absorbed and moved around the body easily.

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79

ingestion

taking in food

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80

absorption

movement of digested food molecules through the walls of the small intestine and into the bloodstream.

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81

assimilation

movement of digested food molecules into the cells of the body where they are used, becoming part of the cells

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82

egestion

passing out of food molecules that have not been digested as feces through the anus

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83

Egestion vs excretion

excretion is things are chemically changed in the cells but egestion is just passing through (???)

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84

digestion can be _, eg. teeth, or _, eg. enzymes

mechanical, chemical

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85

What does saliva do?

Saliva contains the enzyme amylase which breaks down starch and simple sugars (maltose). It also helps food pass into the oesophagus.

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86

What do teeth do?

Teeth break food down to increase surface area. THis makes it easier to swallow and the more surface area, the higher the enzyme activity.

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87

What does the stomach do?

Stomach acid pH 2 helps the enzyme pepsin to break protein into amino acids (optimum pH). It also kills microbes (denatures enzymes).

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88

How does food move down the esophagus?

peristalsis (wave of muscle contractions)

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89

where is bile produced?

the liver

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90

Where is bile stored?

gall bladder and released from the bile duct.

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91

What does bile do?

emulsifies fat (breaks down into smaller droplets) to increase surface area and neutralises mixture of food and gastric juices entering duodenum to provide suitable pH for enzyme activity

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92

What does the small intestine do?

(The small intestine releases amylase) Absorption of food chemicals takes place.

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93

amylase breaks starch down into ______ Protease breaks down protein into ______ Lipase breaks down fats to ______

simple sugars (eg. maltose), amino acids, fatty acids and glycerol

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94

Where do amino acids and glucose go after the small intestine?

blood capillaries

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95

Where do fatty acids and glycerol go after the small intestine?

the lacteals

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96

What are lacteals?

part of the lymph system and drain into the blood

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97

What does the large intestine do?

absorbs water

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98

incisor teeth

cut and bite chunks of food (4 on top, 4 on bottom)

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99

canine teeth

for tearing. Very sharp, pierce food

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100

premolars (bicuspids)

4 of them, for grinding and chewing

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