Understanding Ourselves

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06/13/22 Understanding Understanding Ourselves Ourselves W Richards The Weald School (OCR)

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Understanding Ourselves. (OCR). W Richards The Weald School. Body systems. The RESPIRATORY SYSTEM: takes in _____. The ___________ SYSTEM: transports oxygen and glucose around the body. The SKELETAL and MUSCULAR systems: use the _____ from glucose to allow ________. - PowerPoint PPT Presentation

Transcript of Understanding Ourselves

Page 1: Understanding Ourselves

04/22/23

Understanding Understanding OurselvesOurselves

W Richards

The Weald School

(OCR)

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04/22/23Body systemsBody systems

The RESPIRATORY SYSTEM: takes in _____

The DIGESTIVE SYSTEM: takes in ________

The ___________ SYSTEM: transports oxygen and glucose around the body

The SKELETAL and MUSCULAR systems: use the _____ from glucose to allow ________

Words – energy, movement, oxygen, glucose, circulatory

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04/22/23CirculationCirculation1) Blood gets pumped from the heart to the lungs and picks up oxygen

2) The blood is then taken back to the heart…

3) The heart pumps the blood to the intestine (where oxygen and glucose are removed)…

4) … and to the rest of the body (where oxygen is removed)

5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again

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04/22/23The Circulatory systemThe Circulatory systemThe circulatory system is responsible for pumping ______ around the body. We need blood to be taken around the body because blood contains ________ and _______. These are needed so that all the ____ in our bodies can produce _____ through _________.

Blood is pumped at high pressure. Blood pressure is measured in mmHg (millimetres of ______). Normal pressure is about 120/80 mmHg.Words – energy, mercury, blood,

glucose, respiration, oxygen, cells

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

• Excess weight• High stress levels• _____• Excess _______• Diets that are high in saturated ___, sugar or salt

Long term high blood pressure can cause blood vessels to weaken or even ______.

Words – alcohol, burst, smoking, heart, fat

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04/22/23(Aerobic) Respiration(Aerobic) Respiration

Words – breathing, energy, Mrs Gren, respiration, food

A while ago we learnt about ___ ______. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy:

The glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________.

Glucose + oxygen water + carbon dioxide + ENERGYC6H12O6 + 6O2 6H20 + 6CO2 + energy

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04/22/23Anaerobic respirationAnaerobic respirationUnlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________:

This happens when the body can’t provide oxygen quick enough for __________ respiration to take place.

Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much.

Lactic acid is also produced, and this can build up in muscles causing ______ and an oxygen ______.

This “debt” then needs to be “repaid” by deep breathing to ________ the lactic acid.

Words – debt, oxygen, fatigue, oxidise, aerobic, quicker

Glucose lactic acid + a bit of energy

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04/22/23The Effect of Exercise The Effect of Exercise Heart rate/min

Breathing

rate/min10075

50

25

225

17512575

5 mins 10 mins 15 mins 20 mins

Rest Exercise Recovery

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

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

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04/22/23Modern diets and health Modern diets and health problemsproblems

% obesity in the UK

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04/22/23Poor dietsPoor dietsIf we don’t have a balanced diet we may suffer form a “deficiency symptom”:

Vitamin D

Protein

Vitamin C

Vitamin A

Iron

Calcium

Anaemia

Scurvy (bleeding gums and joints)

Weak bones and teeth

Wasting of body tissue

Rickets

Poor night vision

Lack of… Causes…

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04/22/23Metabolic Rate and healthMetabolic Rate and healthThe rate at which our bodies carry out chemical reactions is called the “metabolic rate”. This rate varies with:• The amount of work we do• The amount of fat in our body• Inherited factors

Condition How this affects our health

Lack of exerciseFatty dietsWarm weatherUsing cars instead of walkingPlaying XBox instead of football

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04/22/23Body-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

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04/22/23ProteinProteinProteins 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?

RDA of protein (in g) = 0.75 x body mass (in kg)

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04/22/23Eating 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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04/22/23The digestive systemThe digestive systemThe whole point of digestion is to break down our food so that we can get the bits we need from it…

The main foods affected are CARBOHYDRATES – these are broken down into GLUCOSE.

Hydrochloric acid is produced in the stomach to kill bacteria. Digestion also depends on “enzymes”...

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04/22/23EnzymesEnzymesEnzymes are chemicals produced by the body to help _______. When they react with food they break it down into ______ pieces which can then pass into the ______:Carbohydrase (produced in the mouth, pancreas and small intestine) breaks _______ (a carbohydrate) down into glucose:Protease (produced in the stomach, pancreas and small intestine) breaks _______ down into amino acids:

Lipase (produced in the pancreas and small intestine) breaks fats (_____) down into fatty acids and glycerol:

Words – blood, lipids, proteins, digestion, starch, smaller

Bloo

dstre

am

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04/22/23Bile and the liverBile and the liverBile is a chemical produced in

the liver and stored in the gall bladder. It has 2 functions:

1) It neutralises stomach acid and produces alkaline conditions for enzymes to work in

2) It emulsifies (“breaks down” fats:

Fat globules

Fat droplets

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04/22/23DiseaseDiseaseA disease is any condition where the body does not work properly. It can be caused by a number of things:

• A spread of infection from another person (an “infectious disease”, e.g. A cold)• Poor diets (e.g. Scurvy)• Organ malfunction (e.g. Diabetes)• Genetic inheritance (e.g. Colour blindness)• Mutations in cells (tumours, e.g. Cancer) – these can be caused by smoking, drinking, too much sun etc

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04/22/23PathogensPathogensPathogens are microbes (micro organisms) that can cause diseases. They can enter the body in a number of ways:

…or other natural openings…

They can be breathed in through the mouth or nose

They can enter through cuts or bites in the skin

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04/22/23DiseaseDiseaseA disease is any condition where the body isn’t working as it should. This could be caused by a malfunction in the body (as with diabetes) or it could be caused by a type of pathogen:

VirusesBacteria

• 1/1000th mm big• Living cells (some are harmless)• Grow very quickly• Affected by antibiotics• Examples: food poisoning, tetanus, sore throats

• 1/1,000,000th mm big• Genetic info inside a protein coat• Not affected by antibiotics• Release poisons• Examples: colds, flu, polio, chicken pox

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04/22/23Using 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”.

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04/22/23FungiFungiFungi can also cause unwanted conditions. These conditions can be treated with anti-fungal medicine and antibiotics. Some examples (don’t look if you’re faint hearted!):

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04/22/23Transmitting DiseasesTransmitting DiseasesPathogens can be transmitted in a number of ways:

1) “Horizontal transmission” (directly ______ an ill person)2) “Vehicle transmission” (touching an ill person’s

________)3) “Vertical transmission” (mother to ____)4) Airborne (______ in the air)5) Vector-borne (third party, e.g. __________)

Words – mosquitoes, belongings, touching, baby, germs

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04/22/23MalariaMalaria

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04/22/23Microbes: 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

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04/22/23Cleaning 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)

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04/22/23White 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)

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04/22/23Producing 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

You’re going down

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04/22/23Specific antibodiesSpecific antibodies

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

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04/22/23Fighting diseaseFighting diseaseNATURAL IMMUNITYThis is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy.

ARTIFICIAL IMMUNITYCan 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 are injected directly into the body – this is called PASSIVE IMMUNISATION.

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04/22/23VaccinationsVaccinationsSome 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

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04/22/23Researching new medicinesResearching new medicinesBefore new drugs can be approved they have to go through three stages:

3. Does it work? People with the illness are tested on. This can involve using a “placebo” – a dummy pill

1. Is it toxic? Tests are done on animals

2. Is it safe for humans? Human volunteers trial the drug

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04/22/23The 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)

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04/22/23Nervous ReactionsNervous ReactionsWhen we react to a stimulus our bodies use the following pattern:

Stimulus Receptor Coordinator Effector ResponseFor example, consider

a man and a camel: Oh No!

What are the stimulus, receptor, coordinator, effector and response in this situation?

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04/22/23Examples 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

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04/22/23Types 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

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04/22/23SynapsesSynapses

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

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04/22/23Conscious 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

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04/22/23Reflex 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…

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04/22/23Reflex actionsReflex actions

1. Receptor

2. Sensory neurone

3. Relay neurone in the spinal chord

4. Motor neurone

5. Effector

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04/22/23VisionVision

“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

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04/22/23Seeing thingsSeeing things

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

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04/22/23Focussing 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.

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04/22/23The Iris ReflexThe Iris Reflex

When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size.

When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size.

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04/22/23Drugs Research ProjectDrugs Research ProjectExplain and give examples for the following:

1) Why do people use legal drugs?

2) What are the drawbacks of legal drugs?

3) Alchohol is a legal drug. What does it do to the human body?

4) Why do people use illegal drugs?

5) What are the drawbacks of illegal drugs? What can they cause?

6) Find out which drugs are in which classes

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04/22/23DrugsDrugsDrug Effect on

nervesEffect on activities

Abnormal behaviour

causedCaffeine/ other stimulants

Barbiturates/ other sedatives

Paracetamol/ other painkillers

Speed up synapse transmissions

Reactions could become faster

Highly strung, leads to exhaustion

Slow down synapse transmissions

May make you drowsy, you shouldn’t drive

Highly addictive, make you irritable

Prevent synapse transmissions

May make you drowsy, you shouldn’t drive

Side effects include dizziness or itchiness

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04/22/23SmokingSmokingCigarettes 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

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04/22/23HomeostasisHomeostasisHomeostasis 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

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04/22/23Maintaining Body Maintaining Body TemperatureTemperature

Cold Hot

Vasodilation

Vasoconstriction

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04/22/23HormonesHormonesHormones 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...

• The pancreas produces _______• The adrenal gland produce ________• The pituitary gland produces FSH and LH• Testes produce __________• Ovaries produce progesterone The adrenal

glandWords – testosterone, glands, bloodstream, insulin, adrenaline

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04/22/23Controlling 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

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04/22/23DiabetesDiabetesDiabetes 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 _________.

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.

Words – insulin, disease, inject, dangerous, eating, pancreas

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04/22/23The Menstrual CycleThe Menstrual Cycle

Hormone concentration

Oestrogen – produced in the _______ and causes the lining of the uterus to ______

Progesterone – produced by the empty ________ and maintains the ______. If egg is _______ progesterone continues to be produced

Words – follicle, lining, ovaries, thicken, fertilised

Thickness of uterus lining

Day 0

Day 7

Day 14

Day 21

Day 28

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04/22/23FertilityFertility

In normal circumstances natural hormones are responsible for releasing the egg and for thickening the lining of the womb. These hormones are produced by the pituitary gland in the brain and in the ovaries.

1) …stimulate the release of eggs

2) …inhibit the release of eggs

The amount of glucose in our blood is an example of a process controlled by hormones. Hormones are “chemical messengers”, produced by glands and tranposrted by blood. Another example of a process controlled by hormones is the menstrual cycle, where hormones can...

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04/22/23Genes, Chromosomes and Genes, Chromosomes and DNADNA

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04/22/23

Some facts: - Made up of paired bases – A links with T and C links with G – to form a “double helix” - Contain instructions on what a cell does, how the organism should work etc - The instructions are in the form of a code - The code is made up from the four bases that hold the strands together - The bases represent the order in which amino acids are assembled to make proteins - Only some of the genes in each cell are “switched on” - DNA can be “mutated” by X-rays, UV, certain chemicals etc

How genes workHow genes work

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04/22/23Sexual 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:

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04/22/23Sexual 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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04/22/23Boy or Girl?Boy or Girl?

X Y X

XX XYGirl Boy

“Allele”

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Father

Mother

Son

Daughter

Boy or Girl?Boy or Girl?

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04/22/23Eye 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?

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04/22/23Eye 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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04/22/23Eye colourEye colourExample 3: A heterozygous brown-eyed father and a blue-eyed mother:

Bb

Bb Bb bbbb

bb

b bB b

Equal (50%) chance of being either brown eyed or blue eyed.

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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

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04/22/23Example 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).

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04/22/23Inherited 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:

2) Huntingdon's disease – a disease of the nervous system that causes shaking and eventually dementia. It’s caused by a dominant allele:

3) Sickle cell anaemia – a disease that alters the shape of red blood cells, thereby reducing their oxygen capacity, causing weakness and anaemia. It’s caused by recessive alleles:

Ff FfX

Cc ccX

Ss SsX

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04/22/23Key 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