5d) Cloning

Cloning plants using tissue culture:

1. Plant with desirable characteristics is selected to be cloned. Small pieces (explants)are taken out from the tips of the stem and the sides of the shoot
2. They are then sterilised to kill any bacteria
3. The explants are then grown in vitro - placed into a petri dish containing a nutrient medium (agar) Has all the nutrients to help it grow and austin hormone
4. Cells in explant divide and grow into a small plant
5. Small plant is taken out of medium and planted in the soil and put into greenhouses so they share the same characteristics as the original 
6. There is agar jelly inside which has nutrients (NPK, Mg, Ca, S and Auxin hormones) to help the cells to divide and grow
7. Can be used to produce commercial quantities of identical plants 

Cloning an adult mammal (dolly the sheep):

1. A body (somantic) cell of Sheep A is taken out as it is the sheep we want to clone and the nucleus is taken out (enucleated) and kept 
2. Then the egg cell of another sheep, Sheep B is taken out, because egg cells can adjust and differentiate (change into different types) and then the nucleus is taken out and thrown away 
3. Nucleus of Sheep A is put into the egg cell of Sheep B
4. This egg cell works like a normal fertilised egg and when it is stimulated with an electric shock it divides (by mitosis) and forms an embryo
5. Once it forms a small embryo it is inserted into the uterus of a different sheep, Sheep C- with a different phenotype to prove that the cloning worked
6. The embryo developed normally and was born as a Clone of the first sheep (A). 

Paper Two- Pros and Cons:

Pros-

Help cure diseases by transferring genes into food and giving it to people 

Could make it possible to have organ transplants by cloning organs 

Useful genetics are passed on to offspring 

Cons-

Cloned animals might not be as healthy as normal ones 

Might be consequences that we're not aware of

5c) Genetic modification/engineering

Restriction Enzymes - Are used to splice (cut) the DNA at the specific site- desired gene, e.g. human insulin. It can either be cut as a blunt or sticky end.

Ligases Enzymes - are used to stick pieces of DNA together

Vectors- something to transfer new DNA:
e.g. plasmids and viruses
Plasmids -

1. Isolate/ take out plasmid from bacterium using a pipette
2. cut apart the plasmid 
3. splice out the required gene using enzymes 
4. The glue using ligases the required gene and plasmid together. This is then called RECOMBINANT DNA. 
5. TRANSGENIC CELLS multiplies and starts producing (e.g. human insulin)  

Viruses-

1. Spice the required gene 
2. Add to the virus
3. Virus injects into the DNA (new organism) and RECOMBINANT DNA forms 
4. You then have a transgenic bacterium

Large amounts of human insulin can be produced by genetically modified bacteria that are grown in a fermenter 

Genetically modified plants:

• Crops can be genetically modified to increase food production in lots of different ways - one way is to make them resistant to insects, another is to make them resistant to herbicides (chemicals that kill plants) 
• Making crops insect-resistant means farmers can spray as many pesticides so wildlife isn't destroyed. It also increases crop yield. 
• Making crops herbicide-resistant means farmers can spray it to kill weeds but not the crops
• Some people are against genetic engineering altogether as they worry that a change in organisms genes might create unforeseen problems

1. Splice the DNA with desired features using the enzymes 
2. Meanwhile take plasmid out of Bacteria (Agrobacterium tumefaciems) and cut to allow space for the gene 
3. glue it together to make it a recombinant DNA 
4. Add the new DNA into a petri dish
5. There is agar jelly inside which has nutirents (NPK, Mg, Ca, S and Auxin hormones) to help the cells to divide and grow

3a) Reproduction

Sexual Reproduction Vs. Asexual Reproduction:

Sexual	Asexual
gametes- sex organs	no gametes
not easily wiped out by disease- resistant	easily wiped out by disease- genes the same
fertilisation	no fertilisation
variation	no variation- clones
Meiosis	Mitosis

Flowering Plants 

Carpel- Female parts:

• Stigma (sticky)- pollen sticks to it 
• style- rod-like section that supports the stigma
• ovule
• ovary- contains female gametes (eggs) 

Stamen- Male parts:

• Anther- contains pollen grains- produce male gametes 
• Filament- stalk that supports anther

Sepal is the small green leafy part that protects the flower bud. 

Insect- pollinated Vs. Wind-pollinated 

	Insect	Wind
Petals	large and brightly coloured to attract insects	small and not brightly coloured
Nectary	To attract insects	absent
Scent	sweet to attract insects	absent
Stigma	enclosed within the flower so that insects must make contact	exposed to catch pollen in the wind
Stamen	quite a lot of anther on the top	exposed and anthers around the filament

Fertilisation- Steps:

1. Pollination takes place when pollen goes on the stigma 
2. Pollen germinates if the grain matches chemicals in stigma (triggered by) 
3. Pollen tubes begin to form and enzymes digests through the style to reach ovary 
4. nucleus of male travels down tube to female nucleus in ovule 
5. Nucleus' fuses together so there is fertilisation and the zygotes form

Different types of seed disperal:

• Mechanical 
• Animal 
• Exploding 
• Wind 
• Tide 

Seed germination:

Conditions

- Water: to activate the enzymes that break down the food reserves in the seed

- Oxygen: for aerobic respiration 

- Warmth/Temperature: For the enzymes inside the seed to work

Steps:

The radicle grows before the plumule as it needs to get water and nutrients- sugars, at the moment comes from the food store (cotyledon) 

Methods of asexual reproduction:
 Natural; budding, bulbs, regeneration
Artifical: cuttings, tissue culture, cloning

Humans 

Parts of the Male Reproductive system:

*testis: where the sperm is kept and produced 

*epididymis: sperm development 

*seminal vesicle: fluid containing fructose enzymes and protein for energy in sperm 

*urethra: carries urine from the bladder and sperm 

*ureter: from kidney to ureter to bladder to urethra 

*scrotal sac: hangs behind the penis and contains the testes

*sperm duct: muscular tube that carries sperm from testis towards the urethra 

Parts of the Female Reproductive system: 

*fallopian tube/oviduct: takes released eggs from the ovary 

*cervix: ring of muscle between the uterus and vagina and keeps baby in place during pregnancy 

*ovary: contains ovum (eggs) 

*uterus(womb): muscular sac and site of fertilisation of egg

*vagina; stretches to allow baby and opening for male penis 

Menstrual Cycle:

Stage One Day 1- when bleeding starts and the lining of uterus breaks down 

Stage Two Day 4 to 14- the uterus builds up again, ready to receive an egg

Stage Three Day 14- Ovum develops and is released, this is called ovulation 

Stage Four Day 14-28- Wall is maintained 

Role of oestrogen and progesterone in the menstrual cycle:

Oestrogen ---> Causes the lining of the uterus to thicken and grow and stimulates the release of an ovum at day 14
Progesterone ---> Maintains the lining of the uterus. When the level of progesterone falls, the lining breaks down

Role of LH and FSH in the menstrual cycle:
FSH ---> stimulates the ovary to get the egg ready for release and secrete oestrogen
LH ---> triggers ovulation after being released by oestrogen

Placenta:
The organ of the uterus of pregnant mammals which allows the transfer of nutrients (water, glucose and oxygen) and waste products (urea, carbon dioxide) between mother and foetus through umbilical cord.

Amniotic Fluid:
Surrounds and protects the developing embryo in a sac protects from bones etc. Protects the embryo against knocks and bumps.

Secondary Sexual Characteristics:
Oestrogen in women causes
*Extra hair on underarms and pubic area
*Hips widen
*The development of breasts 
*Ovum release and start of periods 

Testosterone in women causes
*Extra hair on face and body
*Muscles develop
*Penis and testicles to enlarge 
*Sperm production
*Voice deepens 

2j) Co-ordination and Response

Flowering Plants 

Tropism- growth in response to a stimulus e.g. water and light 

+----------------+----------------+---------------------+----------------------------------+
| Response       | Part of plant  | Direction           | Advantage                        |
+----------------+----------------+---------------------+----------------------------------+
| + phototropism | stem tip       | towards light       | maximise the amount of light     |
+----------------+----------------+---------------------+----------------------------------+
| - phototropism | root tip       | away from the light | less chance of drying out        |
+----------------+----------------+---------------------+----------------------------------+
| + geotropism   | root tip       | towards gravity     | more chance of finding moisture  |
+----------------+----------------+---------------------+----------------------------------+
| - geotropism   | stem tip       | away from gravity   | more chance of finding light     |
+----------------+----------------+---------------------+----------------------------------+
| hydrotropism   | root tip       | towards water       |                                  |
+----------------+----------------+---------------------+----------------------------------+

Auxin- plant hormone produces in shoot tips which controls the direction of growth in response to light

Humans 

homeostatis ----> detection of a change in the body 

normal body temperature ----> 37C

Stimulus ----> Response ----> turn back to normal 

Receptors detect stimuli (sense organs) 

Effectors bring about a response to the stimuli 

Central Nervous System

• brain 
• spinal cord 
• send electrical impulses to effector along motor neurone after receptor detects a stimulus 
• coordinate the response

Reflex Arc

• control reactions in humans
• makes a fast automatic response possible 
• body releases the hormone adrenaline automatically 

+-----------+-----------+-----------------+---------------+----------------+-----------+----------+
| Stimulus  | Receptor  | Sensory neurone | Relay neurone | Motor neurone  | Effector  | Response |
+-----------+-----------+-----------------+---------------+----------------+-----------+----------+

Sensory and motor neurone:

The Eye: 

Different types of hormones;

Name of gland	Hormone	What does it do?
Pituitary	ADH	water regulation
Pancreas	insulin	low blood pressure
	glycogen	high blood pressure
Adrenal body	adrenaline	physical activity
Ovaries	oestrogen	development of female secondary
	progesterone	regulates the menstrual cycle
Testes	testosterone	development of male secondary characterists

2i) Excretion

Flowering plants 

Substance being excreted - Oxygen (O2) 

Origin of these excreted substances- leaf/ photosynthesis 

equations- Carbon Dioxide (6CO2) + Water (6H2O) -------> Glucose (C6H12O6) + Oxygen (6O2) 

Humans 

Organs of excretion in the human body are the lungs, kidneys and skin

Excreted substances- water, urea, potassium 

Why is it important to remove urine- urea is POISONOUS 

The kidney:

The Nephron (which is located in the cortex):

Kidney Machine:

Osmoregulation:

2h) Transport

Flowering Plants 

Phloem tubes transport food 

• living cells with perforated end plates to allow stuff through 
• transport food made in the leaves to all other parts of the plant in BOTH directions

Xylem tubes 

• not living cells 
• thick strong walls- lignin give support 
• carries water and mineral ions from the soil around the plant 
• hollow 

Root hair cell: 

• long hairs
• big surface area- absorbing water and minerals
• water taken almost entirely at the root hairs
• minerals also taken up- against a concentration gradient: 'active uptake' 

Transpiration:

loss of water from aerial parts of a plant leaves by evaporation and diffusion 

Rate of transpiration:

1. Light intensity: the brighter the light, the greater rate of transpiration
2. Temperature: the warmer, the faster transpiration happens due to more energy
3. Wind speed: higher the wind speed, the greater the transpiration rate 
4. Humidity: the drier air around the leaf, the faster transpiration happens

A Potometer can be used to estimate transpiration rates

• use stopwatch to record the distance moved by bubble per unit time
•  

Humans 

Blood has four main components:

1. plasma 
2. platelet
3. red blood cells 
4. white blood cells 

Plasma:

• Pale yellow liquid 
• Carries:
• other components in blood 
• CO2 
• Urea 
• Digested food products
• Hormones 
• Heat energy 

Platelets:

• help blood clot when a vessel is damaged 
• stop you from losing too much blood and other microorgansims from entering the wound 
• mesh of protein called fibrin  

Red blood cells: 

• transport oxygen from lungs to all respiring tissues 
• adaptations:
• biconcave shape- large surface area to release and absorb oxygen 
• haemoglobin- contains iron
• no nucleus- more space 

White blood cells:

Two types: 

1. Lymphocytes
• make antibodies to destroy microorgansims, some persists in blood after disease and give us immunity  
2. Phagocytes 
• Engulf bacteria (pathogens) and are non specific so attack anything that's not meant to be there 

http://www.bbc.co.uk/schools/gcsebitesize/science/21c_pre_2011/disease/diseaseresistancerev5.shtml

Vaccinations:

To avoid some diseases like polio, measles and rubella you can be vaccinated 

Involves-

Injecting dead or inactive pathogens 

Trigger immune response and lymphocytes produces antibodies to attack them 

Some lymphocytes remain in the blood as memory cells so if live pathogens of same types of disease appears the antibodies will kill them at a faster because they (antibodies) will be produced at a quicker rate 

The structure of the heart

The Heart rate;

• when you exercise, your muscles need more energy so you can respire more 
• blood has to flow faster, so the heart rate increases 
• exercise increases the amount of CO2 in your blood
• when receptors in the aorta and carotid artery detect high levels of Carbon dioxide, the brain sends signals to the heart -----> moves more frequently and with more force 
• Adrenaline is the specific receptor of the heart 

Blood vessels:

Artery carries the blood away from the heart 

• have thick walls with elastic fibres and smooth muscles 
• have a small lumen for the passageway of blood 
• contains blood under high pressure 

Vein carries blood to the heart 

• have thin walls with little muscle and elastic tissue 
• have a large lumen for a big passageway for blood 
• contain blood under low pressure
• has valves to prevent the back-flow of blood 
•  

Capillary exchange materials 

• one cell thick to allow quick gas exchange 
• have tiny holes to allow gas exchange 
• a tiny lumen 
• very low pressure 

The circulatory system:

Things for Paper Two are in bold, italics 

2g) Gas Exchange

Flowering Plants 

When plants photosynthesise they use up CO2 from the atmosphere and produce O2 which is a waste product

When plants respire -----> use up O2 and produce CO2 which is a waste product. Movement of gases happens through diffusion. 

Net exchange of gases:

• depends on light intensity 
• photosynthesis -----> during day, but plants respire all the time = energy = live 
• day -----> make oxygen and release use up > CO2 than take in 
• night -----> plants ONLY respire, NOT ENOUGH light so- take in O2 and release CO2 

Leaf Adaption:

1. leaves are broad -----> large surface area: diffusion
2. thin -----> gases travel short distance 
3. air spaces -----> large surface area: gas exchange 
4. stomata -----> let gases and water diffuse/osmosis in and out, closes in the dark, close when water from the roots start to dry up and open and close controlled by guard cells. 

Hydrogen carbonate indicator:effect of light 

Low CO2: Purple <----- Normal: Red -----> High CO2: Yellow 

Humans 

Trachea- takes air to the bronchus 
Bronchi- split air in two lungs (left and right)
Lungs- organ where gas exchange takes place  
Bronchiole- takes air to the alveoli
Alveoli- allows gas exchange to occur 

Intercostal muscles- contract and relax ribs 
Ribs- protect lungs and heart 
diaphragm- muscle holds lungs together

Inhalation:

requires energy: active 

• intercostal muscles and diaphragm contract 
• volume increases 
• ribs up and out 
• pressure goes down 
• air flows in 

Exhalation:

passive 

• Intercostal muscles and diaphragm relaxes 
• volume decreases 
• ribs down and in 
• pressure goes up 
• air flows out

Alveoli:

• large surface area- quick gas diffusion
• thin- gas exchange is quicker and doesn't have to go through loads of cells 
• moving blood-allows more red blood cells to be oxygenated
• air sack 

Smoking:

• damages alveoli- reduces surface area. emphysema- disease
• tar damages cilla- chest infections are more likely
• irritates bronchioles and bronchi[tar]- smokers cough
• carbon monoxide reduces the amount of O2 blood can carry- increase blood pressure
• chemicals can lead to cancer- carcinogens  

Investigation:

• sit still for 5 mins. 1 min count number of breaths you take. 4 mins exercise- stop count breaths (1 min) 
• exercise- increases breathing rate, more O2 and less CO2 
• control variable e.g. temperature of room/area and time spent exercising 

Paper Two in bold, italics