B1 Flash Cards

Pregunta	Respuesta
What is the Metabolic Rate? Name one factor that can affect it.	This is the rate at which chemical reactions take place in the body. People with a higher metabolic rate generally have a higher muscle to fat ratio. It can be affected by Genes
How much more energy is stored in a gram of fat when compared to a gram of carbohydrate or protein?	2 X
What happens if a person has a high level of cholestrol in their blood?	Firstly the cholestrol develops a high risk of plaque building up in blood vessel walls. The plaque slows down the blood flow and a clot may be formed. This can block arteries and cause a heart attack.
Which type of cholestrol is 'good' and why? Which type of cholestrol is 'bad' and why?	HDL is 'good', it removes cholestrol from cell walls, reducing the chance of heart disease. LDL is 'bad', it can cause heart disease.
Define the following terms: Pathogen Toxin Epidemic Pandemic	PATHOGEN - a microorganism that causes disease. TOXIN - a poison EPIDEMIC - when a wide spread of people have a disease PANDEMIC - when a whole country or multiple countries are affected by a disease.
What did Ignaz Semmelweis do to reduce the death rate of pregnant women?	Made all the doctors wash their hands in chlorine water.
What is phagocytosis?	When a type of white blood cell known as a phagocyte surrounds a bacterium and ingests it.
What are antibodies?	These are chemicals released by lymphocytes that are specific to a pathogen. They stick to the pathogen and either kill it or make it easier to destroy.
Describe one method to test for the best antibiotic.	Spread bacteria onto the jelly of a petri dish. Now place paper discs soaked with different antibiotics onto the jelly. Leave for a while and then the antibiotic with the widest area around it is the most effective.
How might bacteria become resistant to antibiotics?	Natural selection
Why do we need to avoid using antibiotics unnecessarily?	Because then there is a greater risk of bacteria becoming resistant to it.
What is Vaccination?	This is when small amounts of dead or inactive pathogen are injected into a person's body. The white blood cells attack them and so the body learns how to defend itself if that disease attacks again.
How do new infectious diseases appear?	When previous strains mutate.
Describe how cultures are grown.	Place a small amount of the microorganism you want to grow into a sterilised nutrient medium. If an inoculating loop is needed sterilise that with a flame. Then seal the agar jelly with the bacteria in the petri dish and store at a temperature lower than 25 degrees C
What type of cell secretes hormones?	Glands
What is used in a nervous response?	Electrical impulses along the nerves.
What do neurones do?	Transmit electrical impulses from receptors to the central nervous system then to an effector (eg muscle)
Describe what happens in the nervous system when you stand on a pin.	A receptor picks up the stimulus. Then a sensory neurone carries an impulse to the spinal cord. When it reaches a synapse a chemical is secreted which diffuses through the gap to the next neurone. An impulse then travels through a relay then a motor neurone to the effector.
How does the body lose: 1. Water 2. Salt 3. Heat	1. Breath, sweat and urine 2. Urine 3. Skin and sweat evaporation
Describe the 4 stages of the menstrual cycle.	1. The PITUITARY GLAND secreted FSH. This causes maturation of eggs and the stimulation of Oestrogen. 2. Oestrogen makes the uterus lining thicken, it inhibits FSH production. 3. LH stimulates release of eggs. 4. As FSH as dropped, so does Oestrogen and the cycle starts again.
Describe IVF	The woman is given hormones to stimulate the production of eggs. These are then mixed with her partners sperm to fertilise, a fertilised egg is placed in the uterus which then develops as a fetus.
Define these terms: 1. Auxin 2. Phototropism 3. Gravitropism	1. A plant hormone that makes cells grow longer. 2. A growth response to light. 3. A growth response to gravity.
What happens if a drug addict stops using a drug?	They suffer from withdrawal.
Name three stages of a drug trial.	1. The drug is tested on human cells. 2. The drug is tested on animals. 3. The drug is tested on human volunteers. They are often done with a double-blind trial.
What are statins?	These are drugs that help people reduce their blood cholestrol levels.
Why are professional sports-people banded from using certain drugs?	Because they can be performance-enhancing. Eg steroids which stimulate muscle growth.
Name 3 ways in which organisms compete.	Mates, Territory and Food.
Why do many organisms adapt to live in extreme environments?	There is less competition there.
Name three adaptations associated with animals that live in cold environments.	Thick fur, Thick layers of fat and Small surface area.
What is the term for an organism that lives in extreme environments?	Extremophile
Name a living factor that has changed the environment of Britain recently.	The introduction of grey squirrels.
What could happen if all the bees dissapeared?	Less pollination = less fruit and vegetables = less food for herbivores = extinction = less food for carnivores = extinction = END OF THE WORLD
How can organisms be used to measure pollution in Britain?	Certain species of lichen do not live at certain sulfur dioxide concentrations. Also river pollution can be measured by the species that live in it.
Why do plants only capture a small amount of the light hitting Earth?	Because alot of light misses the leaves altogether, some light reflects off the surface and some is of the wrong wavelength
How do we calculate te efficiency of energy transfer?	efficiency = (useful energy transferred/original energy in) x 100%
Why is a pyramid of biomass always drawn with a pyramidal shape?	Because energy is lost at every stage.
Why are energy losses from mammals and birds higher than snakes, frogs and fish?	Because they need to keep their body temperature high.
At which temperature do bacteria grow fastest?	Around 20 degrees celsius.
Name three ways of treatng food to reduce decay?	Canning, Pickling and Drying
What is the equation for photosynthesis? What is the equation for respiration?	1. Carbon dioxide + water > glucose + oxygen 2. Glucose + oxygen > carbon dioxide + water
What are chromosomes?	Long sections of DNA
What is variation affected by?	Inherited genes and the environment.
What is a term for the cell produced by fertilisation?	A zygote
What is internal fertilisation?	When the egg is fertilised inside the female's body.
Describe adult-cell-cloning	1. Nucleus removed from a cell 2. Nucleus from another cell is implanted. 3. The cell is given a shock to start reproducing. 4. When the embryo is big enough it is put into a female's uterus.
How have bacteria been Genectically Enigneered to produce insulin?	The insulin gene is inserted into a bacterium. The bacterium reproduces and with it the insulin gene is reproduced.
What is GM?	Genetic Modification
What is Charles Darwin's theory known as?	Natural Selection
How does natural selection work?	1. An organism's offspring might have a genetic variation. 2. This enables the offspring to survive better and pass on it's genes. 3. The species evolves.
What is an evolutionary tree?	A diagram showing how all the organisms of today have a common ancestor.

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