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Biology Paper 1 Flashcards

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1
Q

Eukaryotic Cells

A

Plant and animal cells.
Genetic material enclosed in a nucleus.

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2
Q

Prokaryotic Cells

A

Smaller.
Bacterial cells.
A single DNA loop
Small rings of DNA called plasmids
No chloroplasts/ mitochondria.
Ribosomes, cytoplasm, cell membrane, dna, cell wall

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3
Q

Nucleus

A

Contains genetic material.
Controls activities of cells

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4
Q

Cytoplasm

A

Chemical reactions take place here.

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5
Q

Cell membrane

A

What goes in and out of cell

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6
Q

Mitochondria

A

Release energy by respiration.
Respiration occurs in mitochondria.

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7
Q

Ribosomes

A

Make proteins

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8
Q

Chloroplast

A

Photosynthesis takes place here.
Chlorophyll contains green substance, absorbs light needed.

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9
Q

Food vacuole

A

Contains cell sap to make cell turgid

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10
Q

Cell wall

A

Made of cellulose, supports and strengthens cell

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11
Q

Microscopes : Practical

A
  1. Cut an onion into pieces using a sharp knife.
  2. Peel off a thin layer of onion epidermis from one piece of onion.
  3. Place the onion epidermis onto a microscope slide in a single flat layer.
  4. Add three drops of iodine solution.
  5. Slowly lower a cover slip at an angle onto the onion epidermis.
  6. Place the slide on the stage of the microscope
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12
Q

Microscopes

A

Course adjustment knob- moves stage up and down
Fine adjustment knob- focuses the image
Objective lens-higher magnification

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13
Q

Sperm cells

A

Reproduction, Join with egg cell

Tail- for movement
Mitochondria- energy for movement

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14
Q

Nerve cells

A

Send electrical impulses from one body to another.
Axons to carry electrical impulses to be transmitted everywhere.
Dendrites to connect to other nerve cells

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15
Q

Root hair cells

A

Hairs increase surface area to absorb nutrients and water better.
Thin walls for shorter distance

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16
Q

Muscle cells

A

Mitochondria- provide energy for muscle contraction
contain special protein fibres which can change their length.

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17
Q

Xylem

A

Dead plant cells
Carry water (transpiration)
thick walls containing lignin to prevent collapse
Only up
No internal structures between cells to provide a continuous route for water to flow

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18
Q

metre to micrometer

A

1 m —-> 1 000 000 micrometer

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19
Q

Differentiation

A

cells are specialised

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20
Q

Phloem

A

Living plant cell
Carry simple sugars (translocation)
Have sieve plates let sugars/amino acids up and down the stem
Companion cells to provide energy needed for active transport

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21
Q

Purpose of cell division

A

Growth and development of cells
Repair of cells
Replacement of cells

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22
Q

Cell stages

A

First stage: Longest stage
Cell grows
DNA replicates
Each set of chromosomes are split to end of side of cells.
Nucleus splits
Cytoplasm and cell wall splits to 2 identical cells are formed

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23
Q

Stem cells

A

Undifferentiated cell that can be copied/changed into other cell types.

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24
Q

Human embryo

A

Fertilized egg
Can be differentiated into any cells

May be able to treat conditions like paralysis and diabetes

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25
Q

Adult cells

A

Found in bone marrow
Can be differentiated into blood cells.
Replace dead / damaged tissues

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26
Q

Meristem

A

Plants
Can differentiate to any plant cells
Can be cloned to protect from extinction
Cloned to produce many identical plants

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27
Q

Therapeutic cloning

A

Produces embryo with genes that are same to the patients
Not rejected by body
Transfer of infection, ethical religious objections

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28
Q

SURFACE AREA TO VOLUME

A

SA: 6a2
V: a x a x a

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29
Q

Chromosomes

A

Consist of DNA molecules
Each chromosome carry many genes, which control development of different characteristics eg hair color.

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30
Q

Smallest–>Largest

A

DNA
Gene
Chromosome
Nucleus
Cell

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31
Q

Diffusion

A

movement of particles from a higher concentration to lower concentration down a concentration gradient.

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32
Q

Examples of diffusion

A

Minerals and water diffuse into the plant through the roots.
Food molecules diffuse into the blood stream in small intestine.
Water molecules diffuse into the blood stream in the large intestine.
Oxygen passing from the alveoli to the blood.

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33
Q

Factors which affect the rate of diffusion:

A

-The difference in concentration gradient
-Temperature
- Surface Area

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34
Q

Factors affecting gas exchange:

A

-Large surface area
-A membrane that is thin - short diffusion path
- Efficient blood supply (alveoli)
-Access to air (Ventilation)

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35
Q

Osmosis

A

Diffusion of water particles from a dilute solution (high water concentration) to a concentrated
solution (low water concentration) through a partially permeable membrane.

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36
Q

Osmosis practical

A
  1. Weigh five pieces of carrot.
  2. Place each piece into a different tube.
  3. Into each tube add 20 cm3 of water or one of the sugar solutions as shown in Figure 1
  4. Leave the apparatus for 2 hours.
  5. Remove the carrot and dry each piece on paper towel.
  6. Reweigh each piece.
  7. Calculate the percentage (%) change in mass of each piece.
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37
Q

Isotonic

A

Concentrations of outside and inside solutions are the same.
No change

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38
Q

Hypertonic

A

Concentration of inside solution is less.
Concentration of outside solution is more.
Moves inside, swollen, turns turgid

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39
Q

Describe what would happen if red blood cells are put in a hypotonic solution.

A

water enters the cells (by osmosis)

they burst / lyse / lysis occurs
water leaves and cell shrinks

animal cells have no cell wall or plant cells have a cell wall

cell wall prevents lysis / bursting / allows turgidity

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40
Q

Hypotonic

A

Concentration of inside solution is more.
Concentration of outside is less.
Moves outside, shrinks, turns flaccid

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41
Q

Active Transport

A

The movement of particles from an area of low concentration to an area of higher concentration against concentration gradient using energy.

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42
Q

Examples of Active transport

A

Active transport allows mineral ions to be absorbed into plant by root hairs for healthy growth.

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43
Q

Cells, Tissues, Organs, Organ systems

A

Cells are the basic building blocks of all living organisms.
A tissue is a group of cells with a similar structure and function.
Organs are group of tissues performing specific functions.
Organ systems work together to form organisms.

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44
Q

Tissues

A

Muscular- churns up the food
Glandular- makes digestive juices to digest food.
Epithelial- covers inside and out of stomach.

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45
Q

Salivary glands

A

produces amylase in saliva

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46
Q

Stomach

A

-produces protease

-produces hydrochloric acid, which kills bacteria and right pH for protease to work

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47
Q

Liver

A

Where bile is produced.
Bile neutralises stomach acids, so enzymes work more efficiently, and emulsifies fats, for larger surface area.

Alkaline,

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48
Q

Gallbladder

A

Bile is stored here

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49
Q

Pancreas

A

Produces protease, amylase, and lipase.

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50
Q

Small intestine

A

absorbs nutrients for the body
makes protease, amylase, lipase.

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51
Q

Large intestine

A

absorbs excess water from food.

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52
Q

Rectum

A

Faeces are released here.

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53
Q

Substrate

A

Molecules which the enzymes break down

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54
Q

Enzymes

A

biological catalysts which speed up the reaction without being used up.

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55
Q

Lock and Key

A

Enzymes have a specific active site which only fits one substrate.

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56
Q

Optinum pH

A

6, 7, fastest for reactions to take place.
If too high/low, enzyme will denature and substrate won’t fit active site.
Protease- acidic
Lipase- alkaline

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57
Q

Optinum temperature

A

37 C, human body temperature, as it worked the fastest.
If too high/low, enzyme will denature and substrate won’t fit active site.

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58
Q

Amylase

A

Converts starch to simple sugars.
Made in salivary glands and pancreas
Works in mouth and small intestine

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59
Q

Protease

A

Converts protein to amino acids.
Made in stomach, pancreas and small intestine.
Works in stomach, small intestine.

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60
Q

Lipase

A

Converts lipids into fatty acids and glycerol.
Made in pancreas, small intestine.
Works in small intestine.

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61
Q

Starch

A

Iodine
Turns black/blue

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62
Q

Sugars

A

Benedicts
Prepare water bath, add the solution with foot sample for 5 mins.
Turns brick red.

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63
Q

Protein

A

Biuret
Turns purple.

64
Q

Lipids

A

Ethanol
Turns cloudy emulsion
Sudan III
Layer turns bright red.

65
Q

The effect of pH on the rate of reaction of amylase
enzyme

A

Put iodine solution in every spotting tile.

In 1 test tube, 2 cm3 starch

In 2 test tube, 2cm3 amylase solution

In 3 test tube, 2cm3 buffer solution (pH 5)

Place all 3 test tubes in water bath at 30 degrees, for 10 mins to reach temperature.

Now combine all 3 solutions into 1 test tube and stir.

Immediately put back into waterbath and start stopwatch.

After 30 secs use stirring rod and transfer solution to spotting tile with iodine.

Iodine should turn blue-black, if starch is present.

Now repeat with different ph buffers , 6,7,8

66
Q

Villi in small intestine

A

Increase surface area for absorption of molecules
Thin membrane- short diffusion path

67
Q

Double circulatory system

A

passes through the heart twice.

68
Q

Heart

A

-The right ventricle pumps blood to the lungs .

-The left ventricle pumps blood around the rest of the body

69
Q

Diagram of heart

A

Blood from body comes to Vena cava , to right atrium, then right ventricle to Pulmonary artery to take deoxygenated blood to lungs.
Blood from lungs come to pulmonary vein to left atrium then left ventricle to aorta to take oxygenated blood to body

70
Q

How is heart rate controlled?

A

Group of cells in right atrium, which act as pacemaker.

71
Q

Gas exchange

A

Alveoli——>tiny air sacs, where gas exchange takes place.
Ribcage—-> protect the lungs
Intercostal muscles—->Move the ribcage.
Diaphragm—–> helps with breathing, seperates from rest of the body.
Bronchioles—-> Deliver air to alveoli.

72
Q

Passage of air into lungs

A

Air enters the body and is warmed as it travels through the mouth and nose.

It then enters the trachea.

Trachea has rings of cartilage to prevent collapse during inhalation.
The trachea divides into two bronchi.

Each bronchi branches out into smaller tubes called bronchioles.

Air travels through these bronchioles.

At the end of the bronchioles, the air enters one of the many millions of alveoli where gaseous exchange takes place.

Alveoli are where gases diffuse in and out of blood stream.

73
Q

Adaptations of alveoli

A

millions of alveoli mean that the lungs have a large surface area
They have good blood supply

74
Q

Blood vessels

A

Arteries, Veins, Capilaries

75
Q

Arteries

A

Arteries carry oxygenated blood away from the heart and to the rest of the body.
They have thick walls containing muscle and elastic fibres to help withstand the high pressure created by pumping blood.
This stops the walls from bursting.

76
Q

Veins

A

Veins carry deoxygenated blood towards the heart.
The lumen is wide to allow the low pressure blood to flow through.
Veins have valves to stop the backflow of blood and ensure it flows in the right direction.

77
Q

Capillaries

A

Connect arteries and veins, carry blood really close to every cell.
One cell thick walls to allow exchange of molecules between blood and cells
They have permeable walls so substances can move across them.

78
Q

Blood

A

WBC
Plasma
RBC
Platelets

79
Q

WBC

A

Helps defend the body from pathogens.
Produces antibodies to fight microorganisms.
Contains nucleus, DNA, for instructions to do their job

80
Q

Plasma

A

Transports all blood cells, like nutrients eg glucose.
Carries urea out of your body.

81
Q

RBC

A

Contain red pigment, hemoglobin that binds with oxygen
No nucleus meaning more room to carry oxygen
Biconcave increases surface area. ( doughnut ), so blood diffuses in and out quickly

82
Q

Platelets

A

Helps blood clot at sight of a wound.
Stops pathogens from entering

83
Q

Coronary Heart Disease

A

When arteries become blocked with cholesterol ( fatty materials) meaning less blood flowing to heart, less oxygen supply, increasing heart attack

84
Q

Stents

A

Metal mesh tubes inserted into arteries to keep it open so blood can flow.
Advantages- Lowering the risk of a heart attack.
-Recovery time is quick.
Disadvantages- Blood clots can form near the stent.
- Risk of heart attack during the procedure
-Infection

85
Q

Statins

A

Drug that decreases the levels of bad cholesterol.
Advantages- Increase the levels of good cholesterol.
- Reduce the risk of CHD/ stroke
Disadvatages- Need to be taken continuously and for long term
- Can produce side effects, takes time.

86
Q

Faulty valves

A

When a valve hardens or becomes damaged it begins to leak meaning the blood flows in the wrong direction meaning its not as efficient.

87
Q

Leaky or hardened valves

A

Replacing it with a biological valve (pig or cattle).
Advantages- Works very well
Disadvantages- Only lasts 12-15 years.
Replacing it with a mechanical valve (manmade)
Advantages-Lasts for a long time
Disadvantages- Needs constant medication to stop blood clotting around the valve

88
Q

Heart failure (If irregular heartbeat)

A

Artificial pacemaker
Requires a donor who recently died, artificial.
Electrical device that produces signals making heart beat at normal speed.

Advantages-Less likely to be rejected by the body and immune system

Disadvantages-Surgery temporarily leave the body open to infection.
- Blood clots could form leading to stroke

89
Q

Health

A

A state of physical, mental and social well being .

90
Q

Communicable disease

A

Can be passed from one individual to another.
Caused by pathogens (bacteria, viruses, fungi, protist)

91
Q

Non - communicable disease

A

A disease that cannot be passed from one individual (Cancer, Diabetes, Cardiovascular disease)

92
Q

How do diet, stress and life situations affect health

A

Diet- Too little food, lack of nutrition, vitamin deficiency. Too much food, unhealthy food, obesity Type 2 diabetes.
Stress- health problems, cancer, mental health affect.
Life situations- location, status, can impact a persons mental and physical health.

93
Q

Examples how health problems interact

A

-Viruses living in cells can be the trigger for cancers.
-Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
-Severe physical ill health can lead to depression and other mental illness.

94
Q

Causal mechanism ( 1 factor affects another)

A

-The effects of diet, smoking and exercise on cardiovascular disease.
-Obesity as a risk factor for Type 2 diabetes.
-The effect of alcohol on the liver and brain function.
-The effect of smoking on lung disease and lung cancer.
-The effects of smoking and alcohol on unborn babies.

95
Q

Drugs

A

-Optimal dose
-Effectiveness
-Safety ( non toxic)

Digitalis —- originated fromFoxgloves
Aspirin —– Willow Trees
Pencillin —- Mould

96
Q

Alcohol

A

Can affect brain function
Causes liver cancer

97
Q

Smoking

A

Damages walls of arteries
Nicotine- increases heart rate
Tar- damages lung tissue
Carbon monoxide- Poisonous, takes place of oxygen in blood.
Can lead to lightweight/ premature babies.

98
Q

Cancer

A

Caused by uncontrolled growth, division.

99
Q

Risks of Cancer

A

Smoking
Obesity
UV light
Genes

Radiotherapy
Chemotherapy
Surgery

100
Q

Tumor

A

When DNA in cell becomes damaged
Cells divide uncontrollably and form a mass of cells

101
Q

Benign

A
  • Contained in 1 area
    -They do not invade other parts of the body.
102
Q

Malignant

A

-Not contained in 1 place
-They invade other tissues.

103
Q

Epidermal tissue

A

Covers entire plant.
Has waxy cuticle which helps reduce water loss.

104
Q

Palisade mesophyll

A

Photosynthesis, as contains many chloroplasts.

105
Q

Spongy mesophyll

A

Many air spaces which allow gases in and out.

106
Q

Xylem

A

Made up of dead cells for continuous hollow tube.
Strengthened by lignin, making vessels strong

107
Q

Phloem

A

Sieve plates as they allow organelles to transform

108
Q

Meristem

A

Differentiate into many different cell types allowing plant to grow.

109
Q

Guard cells

A

Control opening and closing of stomata

110
Q

Translocation

A

Movement of dissolved sugars from leaves to the plant

111
Q

Transpiration

A

movement of water from roots / root hairs (up stem) via xylem to the leaves
(water) evaporates, via stomata

112
Q

Factors affecting rate of transpiration

A

Temperature
Humidity
Wind
Light intensity

113
Q

Temperature

A

Increasing temp, increase rate of transpiration.
More kinetic energy, diffuse faster.

114
Q

Light intensity

A

Increases light, increases rate of transpiration.
Stomata is triggered to open, more water leaves.

115
Q

Humidity

A

More humidity, less rate of transpiration
Less water will evaporate

116
Q

Wind

A

Increases wind, increases rate of transpiration
As wind removes boundary layer, more water will evaporate.

117
Q

Pathogen

A

disease causing microorganism eg fungi, protist, bacteria, virus

118
Q

How do bacteria cause disease?

A

Once inside the body, they divide rapidly.
Kill cells and produce harmful toxins

119
Q

How do viruses cause disease?

A

Invade and reproduce inside body cells, leading to cell damage.

120
Q

Fungi

A

grow and penetrate human skin and surface of plants.

121
Q

Protist

A

Live inside other organisms and can cause damage.

122
Q

3 ways pathogens can be spread

A

By air
By water
By direct contact

123
Q

Ways pathogens can be reduced

A

Being hygienic
Destroying vectors
Isolating from infected ppl
Vaccination

124
Q

Measles

A

Virus
Cause blindness and brain damage.
Symptoms are fever and red skin rash.
Spread through by air, coughs and sneezes

125
Q

HIV

A

Virus
Attacks and damages immune system.
Spread by exchange of bodily fluids and sexual contact.
To prevent use condoms, no sharing needles

126
Q

Tobacco mosaic virus

A

Virus.
Infects many plants some maybe discoloured, can’t photosynthesise and affects growth.
Yellow spots
Spread by contact of infected and healthy plants

127
Q

Salmonella

A

Bacteria.
Causes food poisoning.
Symptoms are fever, vomiting, cramps etc.
To avoid vaccinate animals, disinfect hands.

128
Q

Gonorrhoea

A

Bacteria.
Causes by unprotected sex with an infected individual.
Symptoms are yellow/green discharge.
To prevent use condoms, antibiotics.

129
Q

Rose black spots

A

Fungi
Causes purple or black spots on rose leaves.
Reduces photosynthesis.
Spread by wind and water.
To prevent, destroy infected leave

130
Q

Malaria

A

Protist.
Carried from host to host by mosquitoes, and they enter human blood when they feed.
Symptoms like fever, shaking.
To prevent, use insect nets, repellent.

131
Q

How does the skin prevent pathogens from entering?

A

Skin acts as a physical barrier.
Nose has hair and mucus which trap pathogens
Trachea an bronchi have mucus trap pathogens
Stomach produces hydrochloric acid which kills pathogens

132
Q

White blood cells help to defend against pathogens by:

A

-phagocytosis–> WBCs engulf and digest pathogens They produce specific antibodies. antibodies attach to antigens

Antigen- produced by pathogen
Antibody- produced by body

Lympothis- produce antibodies, and they immobilizes antigen, so they don’t move

-antibody production–> protein molecules produced by WBC. Antibodies stick to pathogens a and triggers pathogens to be destroyed.

-antitoxin production–> WBCs release specific antitoxins to neutralise toxins

133
Q

Antibodies

A

Protect you from unwanted substances entering

134
Q

Antitoxins

A

Neutralise a specific toxin

135
Q

Vaccination

A

Patient is injected with dead pathogens.
WBC produce antibodies, and bind to antigens.
If the same pathogen re-enters the body, the
WBC respond quickly and produce the correct antibody
This prevents infection.

136
Q

Painkillers and antibodies

A

Antibiotics cannot kill viral pathogens.
Painkillers are used to treat symptoms, not to kill pathogens.
It is difficult to develop drugs that kill viruses without also damaging the body’s tissues.

137
Q

Preclinical testing

A

Done in a laboratory using cells, tissues and live animals, not humans, as the drug can be very toxic.

138
Q

Clinical testing

A

-Use healthy volunteers and patients.
-Very low doses of drug are given at start
-If the drug is found to be safe, more trials are carried out to find the optimal dose for the drug.
-Placebo- tablet or injection with no active drug in it, some people will get better, as they think they are getting treated, so they believe they are getting better.

139
Q

Double-blind test

A

-The test group received the active drug.
-The placebo (control) group receive a dummy drug which looks exactly like the test drug but it’s got no active ingredient.
-In a double-blind trial neither the patients nor the doctors know which people are receiving the active drug and which are receiving the placebo that’s to stop bias in case the doctors pay closer attention to people receiving the active drug.

140
Q

Photosynthesis

A

Endothermic
carbon dioxide + water—> glucose + oxygen
Limiting factors are:
Light
Carbon dioxide
Temperature
Chlorophyll

141
Q

5 uses of glucose

A

Respiration
Converted to starch for storage.
Produce fat for storage
Produce cellulose for cell walls
Produce amino acids for protein

142
Q

Respiration

A

Exothermic
Mitochondria
glucose + oxygen —-> carbon dioxide + water

143
Q

Why organisms need energy?

A

-chemical reactions to build larger molecules
-movement
-keeping warm.

144
Q

Anerobic respiration

A

Muscles:
glucose —> lactic acid
-built up of lactic acid
Plant and Yeast cells :
glucose —> ethanol + carbon dioxide
-called fermentation, as its important for bread rising and alcoholic drinks.
Glucose isn’t completely broken down, less energy is transferred.

145
Q

Exercise

A

Heart rate increases
Breathing rate increases
Breath volume increases

146
Q

What happens if you have insufficient oxygen?

A

Anaerobic respiration takes place in muscles.
The incomplete oxidation of glucose causes a build up of lactic acid and creates an oxygen debt.
(amount of energy needed to remove lactic acid)
During many hours of activity, muscles become fatigued and stop contracting efficiently.

147
Q

How can farmers use knowledge about limiting factors to increase profits?

A

Can control temp, light, CO2, to get fastest rate of photosynthesis , increasing yield.

148
Q

How is lactic acid transported away from muscles?

A

Blood flows through muscles, transports the lactic acid to liver.
In liver its converted back to glucose

149
Q

Metabolism

A

Sum of all reactions taken place in the body, eg glycerol/fatty acids to lipids, photosynthesis , respiration, excess protein into urea.

150
Q

Metabolic rate

A

Rate at which reactions take place.

151
Q

Practical: Photosynthesis

A
  • measure the distance between the pondweed and the light source
  • count the number of bubbles or measure the volume of oxygen / gas produced
  • (measure oxygen / gas produced) in a set period of time
  • change the distance between the light source and the pondweed or use a different power lamp
  • control colour of light
  • control temperature using a heat screen / water bath
  • use the same pondweed
  • use the same length / size of pondweed
  • control carbon dioxide supply
  • idea of allowing time for pondweed to equilibrate
  • repeat each test two or more times
  • calculate a mean
152
Q

Obesity

A

Type 2 diabetes
Doesn’t respond to insulin
Struggles to control concentration of glucose

153
Q

Virus and bacteria

A

Virus is smaller than bacteria

154
Q

Mitosis

A

Produces diploid cells
Produces cells with 46 chromosomes
Produces genetically identical cells
One cell divison
Produces 2 daughter cells

155
Q

Meiosis

A

Produces haploid cells
Produces cells with 23 chromosomes
Produces genetically different cells
2 cell divison
Produces 4 daughter cells

GCSE Flashcards (8 decks)

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