Biology- Core Flashcards
What is a allele?
A different version of the same gene
Name and describe how white blood cells defend the immune system
- Engulf the pathogen- engulfing stops you feeling ill
- Produce antibodies - these proteins lock on to the antigens of the pathogen and kill the pathogen, if infected again they are easily killed
- Produce antitoxins - these cancel out the toxins released by the pathogen
What is sexual reproduction
Reproduction which involves the fusing of male and female gametes creating offspring that is genetically varied
What is asexual reproduction?
Reproduction that involves NO fusing of the gametes and therefore creates a clone
Describe how tissue culture works?
- A few cells of the plant are taken
- Put in a growth medium with hormones
- expensive probably done in a lab
+ quick, all year round, grown in a small space
Describe how plant cuttings work?
- Take a plant cutting
- Plant the cutting in moist conditions with hormone rooting powder
- Quick and cheap
How does embryonic cloning work?
- Divide each embryo into individual cells
- Cells grow into identical embryos
- Put in host mother
How does adult cell cloning work ?
- nucleus removed from unfertilised egg cell
- Nucleus removed from adult cell
- Adult cell nucleus put in empty egg cell
- Electrocution
- Divide to form embryos
- Implanted in mum
How do you mass produce insulin?
- Insulin gene cut out of human body cell using enzyme
- Plasmid cut out of bacterium and split opened using enzyme
- Insulin put in plasmid using enzyme
- Placed back into bacterium
- Reproduced
- Insulin harvested
What does protein do?
Release energy, cell repair, growth and enzymes
What does fat do?
Release fatty acids, cover organs, warmth, cell membranes and release energy
Why does resistant bacteria occur?
Person does not finish antibiotic Bacteria mutates Reproduces Becomes resistant and hard to kill E.g. MRSA
Why isn’t all energy passed on?
Not all animals are eaten Respiration (cellular) Movement Constant body temperature Waste
Describe the carbon cycle
Plants respire and release CO2
CO2 dissolved in air and water and photosynthesis removes CO2
Organisms respire releasing CO2
Organisms eat plants
Decomposers release CO2 when respiring
Burning fossil fuels causes decay and combustion which release CO2
Equation for photosynthesis
CO2 +H2O > Glucose+ O2
(Light energy)
Equation for respiration
Glucose + O2 > CO2 + H2O (+energy)
Equation for combustion
Burning fuel or wood + O2 > CO2 + H2O
Name the factors which effect the metabolic rate
Proportion if muscle to fat - muscle requires more energy Bigger built as they have more cells Regular exercise Inherited factor Men have a higher metabolic rate
Define a hormone
A chemical messenger which travels through the body in the blood activating target cells
Long time, big area, slow action
What is natural selection?
When individuals in a species mutate or have a variation which is beneficial, this allows them to survive and reproduce better than the others in their species which eventually die off
Name three ways in which the body defends itself
Skin, hair, mucus
Blood clotting
White blood cells
Name health problems with malnourishment
Too little: Poor resistance to infection Irregular periods Slow growth + lack of energy Too much: Arthritis Type 2 diabetes High blood cholesterol and pressure Heart disease
Describe what FSH, LH and oestrogen do
FSH: Pituitary gland Causes egg to mature Stimulates oestrogen Oestrogen: Ovaries Inhibits FSH production Stimulates LH LH: Pituitary gland Releases egg
What is homeostasis?
The maintenance of constant body conditions
How does a vaccination work?
A small quantity of a dead or inactive pathogen is inserted into the body so that the white blood cells can produce antibodies to attack the pathogen making them immune in the future
How do you grow bacteria?
- Sterilise inoculating loop in flame to kill of unwanted bacteria
- Let it cool than put in bacteria
- Zig zag across agar jelly this provides food ti help it grow
- Shut lid quickly to prevent air microbes getting in seal with tape
- Let some O2 in so harmful anaerobic bacteria don’t form
And low temps so harmful pathogens don’t grow
Do oral contraceptives have higher amounts of oestrogen than before?
No because higher amounts of oestrogen were linked with side effects such as blood clots
Give three disadvantages of having IVF treatment
- strong reactions to hormones, abdominal pain, vomiting, dehydration
- multiple births could be dangerous for mother and childs
- increased risk of cancer due to hormonal treatment
How are desert animals adapted to save water and keep cool?
- large surface area compared to volume lose more body heat
- efficient with water produced a small amount of concentrate urine and sweats little
- hot conditions- thin layer of body fat and coat allowing it to lose heat
- camouflaged - sandy colour
How do arctic animals reduce heat loss?
Small surface area compared to volume- reduces heat loss
Well insulated- layer of blubber and fur, blubber not only insulates but is an energy source for when food is little
Camouflage- white fur
How do plants in the desert adapt to reduce water loss?
Small surface area to volume - plants lose water through leaves so having small surface area reduced water loss
Water storage tissue
Maximising water absorption- shallow but long roots absorb water quickly
Deep roots find underground water
How do organisms deter predators?
Armour - thorns or shell
Poisons
Warning colours
What is an extremophile?
An microorganism adapted to live in extreme condition such as salty lakes, high pressures or hot volcanic vents
What do animals compete for?
Space food water mates
What do plants compete for?
Light, space, water and minerals
Name the living factors that cause environmental change?
Infectious diseases
Number of predators
Number of prey or food source
Type of competitors
What are the non-living factors that effect environmental change?
Average temperature
Average rainfall
Air or water pollution
Sunlight
What are the living indicators that measure environmental change?
Lichen - air pollution, sulfur dioxide
Mayfly larvae - water pollution, dissolved oxygen
What are the non-living indicators that show environmental change?
Satellites - measure temperature of sea surface and the amount of snow on ice caps
Weather stations - rainfall temperature
Dissolved oxygen metres - concentration of oxygen in water and how quickly its changing
Why do non prescribed drugs have a greater impact on the population?
Easier to get hold off
Cheaper so whole population takes them
Why is it difficult for people to stop taking certain drugs?
Becomes addictive
What has a drug got to be to pass a drug trial?
Stable
Safe
Effective
Successfully taken in and removed from the body
What is a placebo?
A substance used in clinical trials which does not contain any drug at all, it is used so results can be compared
Why do people take drugs?
Stress Enjoy Peer pressure Relax Background
Why do athletes take anabolic steroids?
Not informed by coach
Advantage
Thinks over athletes are taking drugs
Why do people take cannabis?
Relieve multiple sclerosis
Gateway drug
Cause mental health problems
Describe how a drug has to be processed?
Tested on human cells and tissues Live animals Health human volunteers - low dose then gradually built up to find perfect dose Then on sick people Then wide population The whole population
What is thalidomide now used for?
Leprosy
What is a drug?
A chemical substance which alters chemical reactions in the body
Why do we resemble our parents?
Because genes are passed on to us in the sex cells from you parents
What causes variation?
Genetic or environmental
Why is offspring genetically varied?
It receives a mixture of chromosomes fused together
Name the advantages and disadvantages of GM crops?
Increase yield
Contain nutrients which is good for the third world
Grown elsewhere with no problem
- reduce farmland biodiversity
- might not be safe
- transplanted genes mat get out into the natural environment
What are the advantages and disadvantages of cloning?
Reduced gene pool can lead to a disease wiping them all out
Greater understanding of the development of an embryo
Cloned animals not as healthy as normal ones
Humans may be cloned in the future
What are the advantages and disadvantages of a vaccination?
+ prevent epidemics
+ gets rid of infectious diseases
- bad reaction
- might not work
What is the metabolic rate?
Te rate at which chemical reactions happen in our body
Name the seven food groups?
Vitamin Minerals Water Fibre Fat Protein Carbohydrates
What do carbohydrates do?
Release energy by converting glucose which is used in respiration
What does fibre do?
Prevent constipation
What does water do?
Hydration
Cools body down
Transports substances
What does an antibiotic do?
Kills bacteria without damaging good cells
Why is a virus difficult to kill?
They invade cells so cannot get rid off without damaging cells
How do you prevent resistant bacteria?
Stop over pre scribing
Isolate victims
Keep hospitals clean and wash hands
What is meant by cannabis is a stepping stone?
The effects of cannabis create a desire to try harder drugs
What is meant by cannabis is a “gateway” drug?
Cannabis brings people into contact with drug dealers which can offer them more drugs
What is meant by cannabis is down to “genetics”?
Certain people are more likely to take drugs generally so cannabis users will also try other drugs
What are the effects of smoking?
Causes disease of the heart, blood vessels and lungs
Tobacco smoke causes cancer
Nicotine in cigarettes is very addictive so its hard to stop smoking
What are the effects of alcohol?
Alcohol affects the nervous system and slows down the bodies reactions
Took much leads to poor coordination, impaired judgement and unconsciousness
Excessive drinking can cause damage to liver and brain
Alcohol is addictive
For and against performance enhancing drugs?
Unfair advantage
Athletes may not be fully informed of the serious health risks of the drugs they take
+ own decision
+ sport isn’t fair anyway, different athletes have access to different training facilities, coaches and equipment
What is a double blind trial?
Is one where patients nor doctors know wether the patient is getting a drug or the placebo until the results are gathered this is so doctors monitoring patients aren’t influenced by their knowledge
What are performance enhancing drugs?
Drugs that improve a persons performance in a sport
What are recreational drugs?
Drugs that are used for fun, these can be illegal or legal
What are medicinal drugs?
Drugs that are medically useful like antibiotics
Why do you need a prescription for some drugs and not others?
For some drugs you need a prescription as they can be dangerous if misused
How does alcohol and tobacco have a bigger effect on the uk economy?
NHS spending
Police spending
Loose working days
What is malnourishment?
The condition where the body does not have a balanced diet and therefore an insufficient amount of energy
What are the health risks with obesity?
Arthritis Type 2 diabetes High blood pressure Cholesterol Heart disease
What does exercise do?
Increase the amount of energy we use and decrease the amount of stored fat, boost metabolic rate and builds muscle
What does too much saturated fat lead to?
LDL, bad cholesterol transports fats around body clotting arteries
Name three types of pathogen
Bacteria, viruses and fungi
What is the difference between viruses and bacteria ?
Bacteria reproduce outside the cell whereas viruses reproduce inside the cell
Bacteria are living
What was the john baptise theory?
If a characteristic was used a lot than it would become more developed in its lifetime, it would then pass on the characteristics to the offspring
Why did people object to darwin?
Religious beliefs
Not enough evidence
Difficult to explain
Describe the process of decay?
Detritus feeders and microorganisms break down dead animals and waste to give back the elements to the atmosphere
What are the conditions for decay?
Warm
Moist
Plenty of oxygen
Name ways in which energy was lost?
In waste - not all energy can be digested
By movement and growth - building new cells and respiration
Keeping a constant body temperature
Cellular respiration lets of heat energy to the surroundings
How do you get rid of excess ions?
Lost in sweat
Kidneys = urine
How do you get rid of extra blood sugar?
Insulin
How is water removed?
Skin - sweat
Lungs - breath
Kidneys - urine
How do you control temperature!
Sweat, shiver
Describe reflex arc pathway
Stimulus Receptor Sensory neurone Motor neurone Effector Response
What does a synapse do?
Chemicals are released and diffuse between 2 neurones when they reach the new neurone they send a new electrical signal
What is the purpose of a reflex arc?
To protect and reduce chances of being injured
How do you increase chances of getting pregnant?
LH FSH
How do you stop getting pregnant?
Oestrogen - inhibits FSH
Progesterone - thick cervical mucus which prevents sperm from reaching egg
Name the difference between hormones and nerves
Hormones - slow action, long time, general area
Nerves - quick action, short time, precise area
What are the 4 stages of the menstrual cycle?
1-4 - uterus break down, bleeding
4- 14 - lining builds up
14 - egg released
14-28 - wall maintained unless its not fertilised
Why does shoot go towards light?
Auxin accumulates on shaded side
Unequal distribution
Grows more on shaded side
Bends towards light
Why does shoot go away from gravity?
Auxin accumulates on lower side
Unequal distribution
More growth on lower side
Bends away from gravity
Why do roots grow away from gravity?
Auxin accumulates on lower side
Unequal distribution
Inhibits growth
Grows towards gravity
Why do grow towards moisture
Auxin accumulates on moisture side
Unequal distribution
Inhibits growth
Bends towards moisture
