B1 Flashcards
How can high cholesterol levels in the blood lead to a heart attack
Because high cholesterol can cause a substance called plaque to build up in the artery wall.The plaque slows down the blood and a clot may form.The clot then can block one of the arteries taking oxygenated blood to the heart.this causes a heart attack as the muscle can’t work so won’t beat properly.
What raises blood cholesterol?
Eating saturated fats (found in animal products)
What lowers blood cholesterol?
Unsaturated fats (found in plants)
Good cholesterol?
High density lipoprotein (HDL) as it can protect against heart disease by helping to remove cholesterol from the walls of blood vessels
Bad cholesterol?
Low density lipoprotein (LDL) as it can cause heart disease
Can low levels of cholesterol in blood be inherited?
Yes,from parents
What releases more energy,fat of carbs?
One gram of fat releases almost twice as much energy as one gram of carbohydrates or protein
What’s used for growth and repair?
Protein
What’s all the food groups
Carbohydrates,fats,protein,vitamins,minerals,water,fibre
What can happen if your diet isn’t balanced?
You can become malnourished from lacking in certain nutrients (become too fat or thin) or suffer from deficiency diseases
What’s a metabolic rate?
The rate which chemical reactions take place in your cells
Can metabolic rate be affected by your genes?
Yes what you inherit from your parents
What are carbohydrates for?
Providing quick energy
What are fats for?
Slow releasing energy
What’s protein for?
Growth and repair
What’s fibre for?
Help the digestion system
What’s water for?
Maintains fluid levels and staying hydrated
What are the microorganism that cause disease?
Pathogens
What’s a epidemic?
When a wide spread of people are effected with a disease
What happens when viruses reproduce in the body?
Reproduce in a body cell then destroy it when they burst out the the virus invade other cells
Bacteria reproduction?
Reproduce rapidly inside the body.they may produce toxins (poisons) that make us feel ill
What does a antibody molecule look like?
A letter y
Examples of antibiotics?
Penicillin and streptomycin
What do antibiotics do?
Drugs that kill bacteria inside your body without killing your own cells
On a jelly plate,what does no bacterial growth show?
The antibiotic was more effective
Why can’t you overuse antibiotics?
Because the bacteria can become resistant to them
What does MMR stand fo?
Measles mumps and rubella
What’s a vaccination?
When a small amount of dead or inactive virus that cause the disease are injected in the body.the white blood cells attack it.They remember how to make the antibody so you become immune to the disease
Why can’t some diseases be vaccinated against?
Because there are too many strains of the pathogen I.e common cold
Growing bacteria: what are the microorganisms growing on the nutrient medium called?
Culture
Growing bacteria.avoiding contamination: what must you not do?
You must not touch the algar jelly with your fingers or breathe on it
Growing bacteria:where are the petri dishes kept?
Incubator to keep warm and encourage rapid growth
What are the name of cells nerves contain?
Nerve cells
When hormones affects just a few different organs.what are they called?
There target organs
What is information in the nervous system carried as?
Electrical impulses
What are the cells that transmit electrical impulses called?
Neurones
What’s the back of eye called?
Retina
Where are rod cells
?
Retina.back of eye
What is human body average temp.?
37 degrees Celsius,when enzymes work best?
Where do you gain water?
Food and drink
Where do you loose water?
Breath sweat and urine
What does FSH stand for?
Follicle-stimulating hormone
In the menstrual cycle where is FSH released from?
The pituitary gland
What do the ovaries secrete?
Oestrogen
What do high levels of oestrogen do?
Stop production of FSH
How do contraceptive pills work?
They contain oestrogen which stop FSH being produced so that eggs do not mature
Where is the pituitary gland?
In the brain
What causes the uterus lining to thicken?
Increase in oestrogen
What day in the menstrual cycle are eggs released from the ovary?
Day 14,this is called ovulation
What does IVF stand for?
In vitro fertilisation
How does IVF work?
The women Is given hormones such as FSH to make her ovaries produce several eggs.The eggs are removed and mixed with her partners sperm for fertilisation to occur.One of the embryos is then chosen and placed in the women’s uterus.with luck,it will sink in the uterus lining and make a baby
What are plant hormones used for and why?
Weed killers as they make the weeds grow very fast then die.The hormones only affect weeds because they have a different metabolism
What are recreational drugs ?
Drugs people take to make them feel different
What do steroids do?
Stimulate the body to grow larger stronger muscles!
What do plants compete for?
Light,who ever grows the tallest wins.
What happens in animals if there’s not enough females to go round
?
Males compete for a mate
What are the features called that animals and plants need to survive in certain environments?
Adaptations
What’s do plants that live in dry places have?
Long wide spreading roots to get water,small or no leaves so water doesn’t evaporate away and tissues that can store water
Why do desert animals normally have large ears?
Because a large surface area helps the animal lose body heat and stay cool
Why do animals in cold climates have thick layers of fur blubber and fat?
To insulate them and reduce heat loss,also coloured white for camouflage against snow
Why do plants and animals have thorns,poisons and warning colours?
To deter predators
What are organisms that can live in extreme environments called?
Extremeophiles
What’s a non living factor behind environmental change?
Global warming
What does unpolluted water contain?
A lot of dissolved oxygen
What are the chemicals that glands secrete into the blood
Hormones
What does adrenaline effect?
Heart,breathing muscles,eyes and digestive system
What hormone does the ovary secrete?
Oestrogen
What does the pancreas secrete?
Insulin
What does the adrenal gland secrete?
Adrenaline
What do the testes secrete?
Male sex hormones (especially testosterone)
What are the neurones that transmit impulses from receptors to the central nervous system?
Sensory neurones
Neurone======
Single cell
Nerve====
Bundle of cells as in the spinal cord
What’s a reflex arc?
The pathway taken by a nerve impulse as it passes from a receptor through the central nervous system,and finally to an effector
What are the gaps between neurones?
Synapses
What do synapses do?
Slow down the speed of an impulse
What does your blood have in it?
Ions dissolved in it.The same as those found in salt
How does your body lose heat?
By radiation from the skin,and evaporation of sweat
Oestrogen makes the lining of the__________ grow bigger?
Uterus
What does LH stand for?
Luteinising hormone
FSH and LH are both produced in the Pituitary gland in the brain so how does it reach there target organs?
Through the bloodstream
If pills don’t contain oestrogen,what do they contain?
Progesterone
In plants,what is a growth response to light called?
Tropism called phototropism
What is Auxin and what does it do?
A plant hormone which makes cells in shoots get longer.When light shines on a shoot the auxin builds up on the shady side which makes cells on the other side get longer.So,the shoot bends towards the light.
What’s a growth response to gravity called?
Gravitropism or geotropism
What can cannabis cause?
Mental illness
What are two reasons people die from drug misuse?
1-from the poisoning
2-drugs affect the brain making people behave in a dangerous way
What are statins?
Drugs that help people reduce their blood cholesterol level
For most organisms what conditions are considered lethal?
High temperatures and high pressure
What is the formulae for energy efficiency?
Efficiency=useful energy X 100%
Divided by
Original amount of energy
What’s a pyramid of biomass
Diagram showing energy transfer between organisms,size decreasing at each stage to represent the energy lost
Why does the food chain lose energy?
Some materials and energy are lost in waste materials produced by each organism such as carbon dioxide,urine and faeces
Also resperation in each organisms cells releases energy from nutrients to be used for purposes like movement etc so lots is lost as heat yo its surroundings
What’s compost high in and why?
Compost is high in nutrients and is used to promote plant growth
Bacteria and fungi that carry out decay need:
Oxygen for aerobic respiration
Warm temperatures for enzymes to work at an optimum rate
Moisture for reproduction
What does increasing the temperature of microorganisms do?
Slow or stop decay
What does photosynthesis convert carbon dioxide into?
Carbohydrates and other food molecules such as proteins
If dead organisms don’t decay what happens instead?
Become buried deep and compressed underground and change into fossil fuels
When carbon dioxide is returned to the air when wood or fossil fuels are burnt what’s this called?
Combustion
What are chromosomes?
Long sections of DNA
What are the characteristics that genes contain?
Hair colour eye colour etc
How many sets of chromosomes do sperm and egg cells contain?
One
Why does variation occur?
Because of The genes they inherited (genetic causes) or the conditions in which they developed (environmental causes) or a combo of both
How does fertilisation in animals work?
A new cell called a zygote which divides repeatedly to produce a little ball of cells which develops into an embryo finally turning into an adult animal
What happens in asexual reproduction?
An individual splits into two (as in bacteria) or a part divides off.this is the offspring
If an egg is fertilised outside the body what’s this called?
External fertilisation
What are the three ways of cloning?
1-Taking cuttings then dipped in hormone rooting powder and placed into soil.
2-tissue culture:when a small piece of tissue is taken to grow on jelly
3- embryo transplants
What’s genetics engineering?u
When you genetically modify an organism to produce a unique set of genes
Example of genetic engineering?
Soya beans varieties to give them a gene that makes them resistant to glyphosate
Why are people concerned about GM crops?
1- the genes for a toxin to kill insects could be transferred to a wild plant,which could then disrupt natural food chains
2-effects on humans eating fm food
What was Charles darwins theory?
That species gradually changed from one form to another by natural selection.he thought that in each generation only the best adapted individual s survive and reproduce to pass on their characteristics to the next generation
Why weren’t darwins theory’s accepted?
Everyone was very religious at the time
How does natural selection work
Living organisms produce many offspring.the offspring vary from one another due to differences in genes.some have genes that give them a better chance of survival.they are most likely to reproduce.there genes will then be passed to there offspring
What are mutations?
Unpredictable changes to chromosome s or genes
How do you lose mass?
Use more energy than you take in
What does LH cause?
Ovulation
What does the carbon cycle show?
How carbon moves around the planet
