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B1B1Understanding Understanding

OurselvesOurselves

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Revision LessonsRevision LessonsDoes not contain all of the content for B1 – use Does not contain all of the content for B1 – use

checklistschecklists..\B1 Understanding Organisms\B1 Summary and Checklist\B1 Checklist FOUNDATION.doc

..\B1 Understanding Organisms\B1 Summary and Checklist\B1 Checklist HIGHER.doc

22/04/23The Circulatory systemThe Circulatory systemHeart muscle contracts to make the heart beat. This squeezes blood through blood vessels called __(1)____We need blood under pressure around the body because blood contains ___(2)___ and ___(3)___. These are needed so that all the __(4)__ in our bodies can produce ___(5)__ through ___(6)___.Blood is pumped at high pressure. Blood pressure is measured in mmHg (millimetres of __(7)__). Diastolic and systolic measurements are used. Normal pressure is about 120/80 mmHg.

Words – energy, mercury, arteries, glucose, respiration, oxygen, cells

22/04/23High Blood PressureHigh Blood PressureHigh blood pressure is a condition where the __(1)__ and blood vessels experience extra strain. It can be caused by:

• Excess weight• High stress levels• __(2)__• Excess ___(3)___• Diets that are high in saturated __(4)__, sugar or salt

Long term high blood pressure can cause blood vessels to weaken or even ___(5)___.

Words – alcohol, burst, smoking, heart, fat

22/04/23Now try these!Now try these!1) Nikki’s blood pressure is 150/90mmHg.

Which number is the systolic measurement?

2) What does mmHg mean?3) Her blood pressure is high. What are the

dangers of high blood pressure?4) What lifestyle changes can she make to

reduce her blood pressure? Answers• 150• Millimetres of mercury• Blood vessel burst - Stroke, kidney, brain damage• better/low fat diet, regular exercise, not smoking,

low or no alcohol intake, not overweight, reduce stress levels . Extreme cases = drugs

Heart DiseaseHeart Disease• 1. Smoking – increases BP - carbon monoxide-combines with haemoglobin

reduces oxygen, heart rate increases - nicotine – stimulant – increases heart rate2. Saturated fat – cholesterol builds up-forms a plaque-narrows artery3. High salt levels – body retains too much water – higher volume of blood pumped

Qu. Fatty deposits can build up on coronary arteries. Explain how this can lead to a heart attack

Blood flow is restricted, heart muscle receives less oxygen. A thrombosis may occur blocking blood flow to areas of the heart restricting oxygen so it will die – heart attack.

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Deep Vein Thrombosis (Higher)Deep Vein Thrombosis (Higher)When we don’t move for a long time (e.g. on a plane journey), our leg muscles can’t squeeze the veins in our legs, so blood in the veins begins to move very slowly. A blood clot (thrombosis) may eventually form, blocking the vein and leading to Deep Vein Thrombosis (DVT).

Flight socks can help prevent DVT by applying pressure to the legs, which helps squeeze blood through the veins. Leg exercises can also help to prevent DVT.

Measuring fitness - higher

Strength: amount of weight lifted

Agility: ability to change direction

Flexibility: amount of joint movement

Speed: ability to sprint

Stamina: time of sustained exercise

22/04/23Balanced dietBalanced dietA balanced diet should contain fats, proteins and carbohydrates in roughly these amounts:

It should also contain water, vitamins, minerals and fibre.

22/04/23Balanced dietsBalanced diets

Carbohydrate

Protein

Vitamin C

Water

Iron

Fats

Make haemoglobin

To prevent Scurvy (bleeding gums)

Energy store and insulation

Growth and repair

Provides energy

Prevent dehydration

Nutrient Function

22/04/23ProteinProteinProteins are long chains of amino acids. There are two main types of these:• Essential amino acids (must be eaten)• Non-essential amino acids (can be made in the body)

Meat and fish are “first class” proteins

People who do not eat enough protein will not grow properly. Protein deficiency can result in a disease called kwasiorkor, where the muscles waste away and the belly swells.

How much protein should we eat?

EAR of protein (in g) = 0.6 x body mass (in kg)

Food storage - higherFood storage - higher• How are fats, carbohydrates and proteins stored

in the body?• Carbohydrates stored in liver as glycogen or

converted to fats• Fats stored under skin and around organs –

adipose tissue• Proteins can’t be stored. First class proteins

(meat, fish) contain all essential amino acids that can’t be made by the body. Second class proteins (plant proteins) don’t contain all essential amino acids

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22/04/23Body-Mass IndexBody-Mass IndexA commonly-used way to indicate is someone is overweight or underweight is the Body Mass Index (BMI):

BMI = Mass (kg)Height2 (m2)

BMI Meaning<18.5 Underweight

18.5-25 Ideal25-30 Overweight30-40 Obese

22/04/23Try theseTry these1) Elaine is 1.78m tall and has a mass of

66kg. Calculate her BMI.2) Anthony is not overweight. Why could

his BMI be so high? 3) What is EAR of protein and why is it

important?4) What does EAR depend on? (higher)5) What can a balanced diet depend on?- 66/(1.78)2

- Doesn’t account for muscle mass

- Estimated Average daily requirement of protein, eating too little protein – kwashiorkor

- Age and pregnancy

- Age, gender, physical activity, religious, personal, medical reasons

22/04/23Eating disordersEating disordersAnorexia nervosa – this is a condition where sufferers restrict what they eat and sometimes starve themselves, leading to possible weight loss, abdominal pains, discoloured skin, irregular periods etc.

Bulimia nervosa – this is when people vomit or take laxatives straight after eating to get the food out as quickly as possible. It can lead to weight fluctuations, poor skin, hair loss, irregular periods, tiredness etc.

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Now try this!Now try this!

1) Link each food type to the correct product.

Food Enzyme Product

Carbohydrate

Amino acids

Protein Fatty acids

Fat Glucose

FitnessFitness and and HealthHealth• Joe catches a cold. He is surprised

because he is very fit.• His coach explains that being fit does not

stop bacteria and viruses entering his body and causing infections.

Q. What is the difference between fitness and health?

• Fitness is the ability to do physical activity.

• Healthy is being free from disease.

22/04/23MalariaMalaria

22/04/23Now try this!Now try this!1) What is a pathogen?2) Give 4 examples of pathogens3) What is the best way to control malaria?4) A mosquito is which of the following?o Parasiteo Preyo Vector1) A micro-organism that causes disease.2) Fungi, bacteria, viruses, protozoa3) Spray/drain stagnant water,

Insecticides, mosquito nets4) Vector

22/04/23Microbes: our defence against Microbes: our defence against themthem

Our bodies have defence mechanisms against invading microbes:

If our skin is cut platelets seal the wound by clotting

The breathing organs have hairs and produce mucus to cover the lining of these organs and trap the microbes

The skin acts as a waterproof barrier

Our blood contains white blood cells

Tears contain lysozyme, an enzyme that kills bacteria

22/04/23Cleaning our airCleaning our airOur respiratory system has two types of specialised cell that help to keep our lungs clean:

1. Mucus is produced and traps dust, bacteria etc

2. The mucus is swept upwards to the mouth by cilia (cells with tiny hairs)

22/04/23White blood cellsWhite blood cellsIf microbes enter our body they need to be neutralised or killed. This is done by WHITE BLOOD CELLS:

White blood cells do 3 things:1) They eat the microbe (these

white blood cells are called “phagocytes”)

2) They produce antibodies to neutralise the microbe (“lymphocytes”)

3) The produce antitoxins to neutralise the poisons produced by microbes (lymphocytes again)

22/04/23Producing antibodiesProducing antibodies

Step 1: The lymphocyte “sees” the pathogen (microbe)

Step 2: The cell produces antibodies to “fit” the pathogen

Step 3: The antibodies fit onto the pathogens and cause them to “clump”

Step 4: The pathogens are “eaten” by the white blood cells. Some memory cells stick around!

You’re going down

22/04/23Specific antibodiesSpecific antibodies

Antibodies are specific – they will neutralise the microbe they have been made for.

22/04/23Fighting diseaseFighting diseaseImmunisationCan be done in two ways:1) A vaccine with dead microbes is injected – the

body is “tricked” into producing antibodies ready for the real thing. This is called ACTIVE IMMUNISATION

2) The antibodies made by another organism are injected directly into the body – this is called PASSIVE IMMUNITYName two differences between passive and active immunity.Active has a lasting effect but may take a few weeks to become effective

22/04/23VaccinationsVaccinationsSome people argue that the MMR vaccine is a good idea, others think it is a bad idea. Briefly summarise each side of the argument:

MMR vaccine

For Against

22/04/23Using AntibioticsUsing AntibioticsAntibiotics can be used to kill bacteria. However, there

are two problems: 1) Overuse of antibiotics can lead

to bacteria becoming resistant (e.g. the MRSA “superbug”). This means that antibiotics must be used sparingly.

2) Antibiotics have no effect on a virus, like the common cold. It is difficult to kill a virus without damaging body tissue. A virus is usually allowed to “run its course” or with the use of antivirals

22/04/23Now try these!Now try these!1) Fill in the gaps!

Antibodies are made by our ________. Antibodies lock onto ___________ on the surface of a _____________. Antibiotics do not kill pathogens such as ____________.

A ________ is a harmless pill that can have a positive psychological effect.

A ______ is where volunteers don’t know which treatment they’re receiving

A________ is where the doctors don’t know either

White blood cells, passive, blind trial, antigens, pathogen, double blind trial, active, viruses,

placebo

22/04/23The Nervous SystemThe Nervous SystemThe CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors.

Types of receptor:1) Light receptors in the eyes2) Sound receptors in the ears3) Taste receptors on the tongue4) Smell receptors in the nose5) Touch, pressure and temperature receptors in the skin6) Changes of position receptors in the ears (balance)

22/04/23Conscious actionsConscious actionsA conscious action is one where the brain makes a considered response. Here’s what happens:

Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response

1) Receptors in your skin detect a stimulus

3) Here another sensory neurone carries the signal to the brain

4) The brain decides to move away the hand

5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord…

2) The impulse is carried by SENSORY NEURONES to the spinal chord

6) Which then moves the hand away

22/04/23Examples of reactionsExamples of reactionsStimulus Receptor

(i.e. the thing that detects the stimulus)

Effector (i.e. the thing that will do

the reaction)

Response (i.e. action

taken)

Bright light

Sour taste

Losing balance

Sit on a drawing pin

22/04/23Types of nerve cellTypes of nerve cellNucleus Muscle strands

(effector)Cell body

1) Motor neurone 2) Sensory neurone 3) Relay neurone

Impulse Impulse

Nerve cells (neurones) are elongated with branched endings to connect to many muscles

fibres.

Dendrites

22/04/23Synapses - higherSynapses - higher

Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse. These transmitters are then ________.

Words – chemical, synapse, neurone, touch, destroyed

22/04/23Reflex actionsReflex actionsSometimes conscious action is too slow to prevent harm, e.g…

In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

22/04/23Reflex actionsReflex actions

1. Receptor

2. Sensory neurone

3. Relay neurone in the spinal chord

4. Motor neurone

5. Effector

6 mark question - Higher6 mark question - Higher22/04/23

The quality of written communication will be assessed in your answer to this question. Describe how neurones are adapted to carry and pass on nerve impulses quickly from one neurone to the next.

22/04/23Level 3 Answer correctly applies knowledge of how and why neurones are adapted being long, having branched endings and insulated by a fatty sheath There should be reference to the synapse and how this allows impulses to travel in one direction (see diagram). All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how neurones are adapted and how the synapse is the gap between two neurones to allow nerve impulses to travel in one direction . For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple neurone and synapse description. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

6 marker question - 6 marker question - FoundationFoundation

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Explain why active immunity is used for an outbreak of a disease over passive immunity.

The quality of written communication will be assessed in your answer to this question.

22/04/23Level 3 Answer correctly applies knowledge of active immunity to give a well-reasoned explanation of how dead or inactive pathogens are injected into the body and how they trigger your immune system to make their own antibodies and that this is usually permanent. There should be reference to passive immunity and how this is only temporary involving injecting antibodies directly. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of active and passive immunity to give a partial explanation of how immunity is different and why active is better in this case. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple immunity description, recognising that active immunity is different to passive immunity. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

22/04/23VisionVision

“Binocular vision” “Monocular vision”

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Suspensory ligaments

Optic nerve

The EyeThe Eye

Retina

Pupil

Cornea

Ciliary musclesSuspensory ligaments

Optic nerve

Lens

Iris Sclera

22/04/23Seeing thingsSeeing things

Rays of light are refracted (bent) first by the cornea and then by the lens. They focus on the retina.

22/04/23Focussing on different distancesFocussing on different distancesFor distant objects the ciliary muscles

relax and the suspensory ligaments pull tight making the lens pull thin – the

light doesn’t bend as much.

For close objects the ciliary muscles

contract allowing the lens to go fat, thus bending the light

more.

When an eye focuses this is known as accomodation

Correcting eye sight Correcting eye sight problemsproblems

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Long sighted people are unable to focus on ______ objects. The eyeball is too ________, so the image of near objects are brought into focus behind the retina. You can use glasses or contact lens with a ________ lens to correct it

Short sighted people are unable to focus on _______ objects. The eyeball is too _________, so the image of distant objects are brought into focus in front of the retina. You can use glasses or contact lens with a _________ lens to correct it.

Concave, convex, short, long, near, close

22/04/23Drugs Drugs Depressant

Hallucinogen

Stimulant

Painkiller

Performance enhancer

Build muscle to allow athletes to train harder

Distort what is heard or seen

Decrease activity of the brain

Increase the activity of the brain

Reduce no. of painful stimuli

Asprin

Alcohol, solvents

Anabolic steroids

Nicotine, ecstasy

LSD

Try theseTry these• 1. Which class of drug is the most dangerous,

give some examples.• 2. Higher – Explain how the effects of alcohol are

different from nicotine.• 3. Why do people get smokers cough?• Class A – heroin, LSD, ecstasy, cocaine• Nicotine is a stimulant so more neurotransmitter will

cross to the next neurone, whereas alcohols a depressant so binds to receptors to block impulses/slow down

• Smoke stops cilia from moving and makes goblet cells produce more mucus. Dust collects and irritates

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22/04/23SmokingSmokingCigarettes contain 3 harmful things:1. NICOTINE, which is an ___________ drug that raises the

heart beat, narrows the arteries and so causes ____ _____ _____. This leads to heart _________.

2. TAR, which coats the lining of the _______ making them less able to take in oxygen. It also contains carcinogens which cause ______________.

3. CARBON MONOXIDE, which is a _______ ____ which joins up with ____ blood cells making them incapable of transporting _____________ around the body. In pregnant women it can cause oxygen deprivation, leading to low birth ______.Words – high blood pressure, oxygen, red, addictive,

disease, poisonous gas, lungs, cancer, mass

22/04/23HomeostasisHomeostasisHomeostasis means “controlling internal conditions”:

Waste products that need to be removed + howCO2

Urea

Internal conditions that need controlling + howTemperature

Ion contentWater

contentBlood

glucose

Produced by respiration, removed via lungsProduced by liver breaking down amino acids,

removed by kidneys and transferred to bladder

Increased by shivering, lost by sweatingIncreased by eating, lost by sweating + urine

Increased by drinking, lost by sweating + urineIncreased and decreased by hormones

22/04/23Maintaining Body Maintaining Body TemperatureTemperature

Cold Hot

Vasodilation

Vasoconstriction

6 marker -Foundation6 marker -FoundationThe quality of written communicationwill be assessed in your answer to thisquestion. • It is important to keep the body

temperature at 37oC as this is the optimum temperature for many enzymes.

• Explain what would happen if a person gets too hot and how homeostasis helps us to cope with this.

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22/04/23Level 3 Answer correctly applies knowledge of dangers of overheating, such as heat stroke and dehydration. Understanding shown that blood flowing at the surface of skin increases heat loss and explanation of how sweating cools the skin down by evaporation. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of overheating and brief explanation of sweating. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple description that people sweat to cool down and brief description of dangers of overheating. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

6 marker -Higher6 marker -HigherThe quality of written communicationwill be assessed in your answer to thisquestion.

• Explain using negative feedback how the hypothalamus helps to maintain body temperature.

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22/04/23Level 3 Answer correctly applies knowledge of increased temperature of blood detected by hypothalamus so increased sweat production and vasodilation in an attempt to lose more heat. This increases concentration of blood which results in less urine production to conserve water. Understanding of negative feedback – change in environment trigger a response that counteracts the changes. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how the hypothalamus helps to keep our body in balance by detecting when the blood is too hot or cold. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states simple description that hypothalamus detects blood temperature change. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

22/04/23HormonesHormonesHormones are “chemical messengers” produced by endocrine _____. They control the way in which parts of the body work and are transported to their target organs in the _______. Some examples...Words – testosterone, glands, bloodstream, insulin, adrenaline

22/04/23Controlling Blood Sugar Controlling Blood Sugar levelslevelsWe need glucose in our bodies to help our cells to respire

and produce energy. What happens if we have too much glucose?

If blood sugar is too high the pancreas releases

insulin

The liver then converts glucose into insoluble

glycogen and is removed from the blood

22/04/23DiabetesDiabetesDiabetes is a ________ in which a person’s blood sugar (i.e. glucose) level may rise to a _______ level. This is because the ______ doesn’t produce enough _________. Type 1 diabetes is when the pancreas doesn’t produce insulin. Glucose is removed from the blood by the kidneys glucose is excreted in the urine. It usually occurs in teenagers.Type 2 diabetes occurs when the body either produces too little or the cells won’t react to insulin. It is more common in older people and is linked to obesity.Diabetes can be treated by __________ carefully or by injecting extra insulin when needed. Diabetics have to test their blood sugar level before they decide how much insulin to _______ themselves with. A new technique is the insulin pump, its constantly changed for you.

Defining tropismsDefining tropisms

Higher - Hormones and Higher - Hormones and phototropismphototropism

Uses of plant hormonesUses of plant hormones

• Take a cutting - A cutting is taken from the plant and dipped in this powder. This stimulates the roots to grow quickly and enables gardeners to grow lots of exact copies of a particular plant.

• Selective weedkillers -They kill the weeds by making the weed grow too fast, so it dies off faster.

• Seedless fruit - Synthetic auxins are sprayed on un-pollinated flowers. The auxins make the sterile flowers produce fruit. The fruits produced will have no seeds (pips) e.g. Seedless grapes

• To ripen fruit in transport - Bananas are picked when they are green and unripe and less easily damaged. Application of a hormone ensures that when they arrive at the shops they are yellow and ripe.

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Describe 4 uses of plant hormones

22/04/23Sexual ReproductionSexual Reproduction

The human egg and sperm cell (“GAMETES”) contain 23 chromosomes each.

When fertilisation happens the gametes fuse together to make a single cell called a ZYGOTE. The zygote has 46 chromosomes (23 pairs) and contains information from each parent.

We have similar characteristics to our parents due to genetic information being passed down in genes through gametes:

22/04/23Sexual vs. Asexual Sexual vs. Asexual reproductionreproduction

Sexual reproduction:•2 parents are needed•Offspring will have “pairs” of chromosomes•This will cause genetic variation

Asexual reproduction:•Only 1 parent needed•Offspring are GENETICALLY IDENTICAL to parent (“clones”) “Snuppy” – the

first cloned dog (Aug 05)

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Father

Mother

Son

Daughter

Boy or Girl?Boy or Girl?

22/04/23Eye colourEye colourIn eye colour the brown eye allele is dominant, so we call it B, and the blue eye is recessive, so we call it b:

bbBB Bb

Homozygous brown-eyed

parent

Heterozygous brown-eyed

parent

Blue-eyed parent

What would the offspring have?

22/04/23Eye colourEye colourExample 1: A homozygous brown-eyed parent and a

blue-eyed parent:

Example 2: 2 heterozygous brown-

eyed parents

BB bbX Bb BbXParents:

Gametes:

Offspring: Bb Bb BbBb BB Bb bbbB

B B bb B bB b

(FOIL)

All offspring have brown eyes

25% chance of blue eyes

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B bbb

Another methodAnother methodExample 3: A heterozygous brown-eyed father and a blue-eyed mother:

B bb Bb bbb Bb bb

Father

Mother

22/04/23Example questionsExample questions1) In mice, white fur is dominant. What type of offspring would you expect from a cross between a heterozygous individual and one with grey fur? Explain your answer with a genetic diagram.

2) A homozygous long-tailed cat is crossed with a homozygous short-tailed cat and produces a litter of 9 long-tailed kittens. Show the probable offspring which would be produced if two of these kittens were mated and describe the characteristics of the offspring (hint: work out the kitten’s genotype first).

22/04/23Inherited diseasesInherited diseases1) Cystic fibrosis – a disease that causes thick and sticky mucus to coat the lungs, gut and pancreas. It’s caused by recessive alleles:

Cc CcX

22/04/23Key wordsKey wordsGamete

Zygote

Allele

Dominant

Recessive

Homozygous

Heterozygous

•This allele determines the development of a characteristic•This is formed when an egg is fertilised by a sperm•This allele will determine a characteristic only if there are no dominant ones•This word refers to a pair of chromosomes being made of two different alleles of a gene•An egg or a sperm are called this•This word refers to a pair of chromosomes being made of two of the same alleles of a gene•An alternative form of a gene