GCSE biology Flashcards
what are some abiotic factors?
7
moisture level light intensity temperature carbon dioxide level wind intensity and direction oxygen level soil pH and mineral content
what are some biotic factors?
4
new predators arriving
competition
new pathogens
availability of food
what are some ways to study the distribution of an organism?
2
measure how common an organism is in two sample areas (using quadrats) and compare them
study how distribution changes across an area (by placing quadrats along a transect)
what is the 1st step to use quadrats to study distribution of small organisms?
place a 1m(2) quadrat on the ground at a random point within the first sample area (divide the area into a grid and use a random number generator to pick coordinates)
what is the 2nd step to use quadrats to study distribution of small organisms?
count all the organisms within the quadrat
what is the 3rd step to use quadrats to study distribution of small organisms?
repeat steps 1-2 as many times as you can
what is the 4th step to use quadrats to study distribution of small organisms?
work out the mean number of organisms per quadrat within the first sample area (total number of organisms/number of quadrats)
what is the 5th step to use quadrats to study distribution of small organisms?
repeat steps 1 to 4 in the second sample area
`what is the 6th step to use quadrats to study distribution of small organisms?
finally compare the two means
how can you calculate the population size of an organism in one area?
(2)
- work out the mean number of organisms per m(2)
2. then multiply the mean by the total area of the habitat
what are biotic factors?
living things in our environment (e.g. food)
what does population mean?
all organisms of one species living in a habitat
what are abiotic factors?
non-living factors in our environment e.g. temperature
what does habitat mean?
the place where an organism lives
describe the system that classifies living organisms
7
kingdom phylum class order family genus species
what did Carl Woese do and when?
in 1990 he developed the 3 domain system
Woese discovered that species that had once been thought to be closely related by traditional systems were not as closely related as first thought
what are organisms split into in Carl Woeses system?
bacteria
archaea
eukaryota
what consists within the archaea group?
organisms that are primitive bacteria, often found in extreme places such as hot springs and salt lakes
what consists within the bacteria group?
pure bacteria such as E.coli. Although they are similar to archaea there are lots of biochemical differences between them
what do evolutionary trees do?
- they show us how scientists think that species are related
- they show common ancestors and the relationships between different species
how are organisms named in the binomial system?
they are given a two part Latin name
- the first part refers to what genes the organism is from
- the second part relates to what species it is
why is the binomial system helpful?
the binomial system is used worldwide and means that scientists from other countries or that speak different languages all refer to the same species by the same name-avoiding confusion.
what consists with the eukaryota group?
a wide range of organisms such as protists, fungi, plants and animals
what are organisms named after?
the binomial system
what is the 2nd step to check for lipids?
use a pipette to add 3 of drops of sudan III stain solution to the testing tube and mix the contents by shaking the tube
what is the 3rd step to check for lipids?
sudan III stain solution stains lipids. If lipids are present the solution will seperate out into 2 layers, the top layer will be bright red
what is the 1st step to check for lipids?
prepare a food sample and add 5cm(3) to a test tube
what is the 2nd step to check for proteins?
add 2cm(3) of biuret solution to the test tube and shake the tube to mix the contents
what is the 3rd step to check for proteins?
if protein is present the solution will change from blue to purple
what is the 1st step to check for proteins?
prepare a food sample and add 5cm(3) to a test tube
what is the 2nd step to check for starch?
add 5cm(3) of iodine solution to the test tube, if starch is present the solution will change from browny-orange to black or blue-black
what is the 1st step to check for starch?
prepare a food sample and add 5cm(3) to a test tube
what is the formula to calculate the rate of reaction?
rate=1000/time
what do carbohydrase’s do?
they break down carbohydrates into simple sugars (maltose)
what is the 8th step to calculate the effect pH on enzyme activity?
remember to control any variables to make the experiment a fair test
what is the 7th step to calculate the effect pH on enzyme activity?
repeat the experiment several times with buffer solutions of different pHs to see how pH effects the rate of the starch being broken down.
what is the 6th step to calculate the effect pH has on enzyme activity?
use continous sampling to record the time the amylase solution takes to break down the starch. To do this use a dropping pipette to put a drop of fresh solution onto a spotting well every 30 seconds. Once the solution remains browny-orange colour starch is no longer present
what is the 5th step to calculate the effect pH on enzyme activity?
immediately mix the contents of the test tube and start a stop clock
what is the 4th step to calculate the effect of pH on enzyme activity?
next use a different syringe to add 5cm(3) of a starch solution to the boiling tube
what is the 3rd step to calculate the effect of pH on enzyme activity?
using a pipette add 1cm(3) of amylase solution and 1cm(3) of a buffer solution with pH of 5 to a boiling tube. using test tube holders, put the tube into the beaker of water and wait 5 minutes
what is the 2nd step to calculate the effect of pH on enzyme activity?
place a Bunsen burner on top of a heat proof mat and a gauze and tripod onto of the Bunsen burner. Place a beaker of water on top on the gauze and heat it until it is 35 degrees (use a thermometer to measure the temperature) try and keep the temperature of the water relatively constant throughout the experiment.
what is the 1st step to calculate the effect of pH on enzyme activity?
put a drop of iodine solution into every well of a spotting tile
what is a ecosystem?
the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
what does distribution mean?
where an organism is found
what does community mean?
the populations of a different species living in a habitat
what is the 2nd step of the hearts circulation of blood?
the atria contact, forcing the blood into the ventricles
what is the 3rd step of the hearts circulation of blood?
the ventricles contract, forcing the blood through the pulmonary artery and aorta and out of the heart
how do you calculate the rate of blood flow?
volume of blood/number of minutes
what are the 4 heart chambers?
the right atrium
the left atrium
the right ventricle
the left ventricle
what is the 4th step of the hearts circulation of blood?
the blood goes around to all of the bodies cells, it does this through arteries and comes back to the heart through veins
what is the 5th step of the hearts circulation of blood?
the atria fill and the whole cycle repeats
what is the formula to calculate the rate of reaction?
rate=1000/time
what is the pituitary gland?
often referred to as the ‘master gland’-it secretes several hormones and stimulates some organs to secrete hormones in order to balance bodily conditions
what is the endocrine system?
a group of glands that secrete hormones into the bloodstream
what are the 2 main types of cells?
prokaryote
eukaryote
what does oestrogen do?
it causes the uterus lining to grow and helps maintain the lining from day 14 to day 28
-inhibits the release of FSH and stimulates the release of LH
what is the first stage of the menstrual cycle?
day 1-menstuation begins-the uterus lining starts to break down (lasts for 4 days)
what is a hormone?
a chemical produced by a gland, secreted into the blood that has a biological effect on a target organ
what does the pancreas do?
- produces digestive enzymes amylase, protease and lipase
- releases these into the small intestine
why do organisms need energy?
contraction
homeostasis
groeth
what is the dependent variable?
the thing you measure
what are some properties of hormones?
- long lasting
- slower reaction
- react in a more general way
what is the fourth stage of the menstrual cycle?
the uterus lining is maintained from day 14 to day 28, at day 28 if no fertilized egg is implanted into the lining the uterus lining breaks down and the whole cycle repeats. but if a fertilized egg is implanted the cycle stops.
what does progesterone do?
maintains the uterus lining from day 14 to day 28, when the levels of progesterone falls the lining breaks
-inhibits the release of LH and FSH
what is the fifth step of the photosynthesis practical?
calculate the average number of bubbles produced per minute, repeat the experiment at different distances away from the light source
what is the fourth step of the photosynthesis practical?
position the boiling tube so that the pondweed is 10cm away from the light source. Allow the boiling tube to stand for 5 minutes. Count the number of bubbles emerging from the cut stem in 1 minute. Repeat the count 5 times and record your results.
what is the third step of the photosynthesis practical?
use forceps to place the pondweed in the boiling tube carefully. Make sure that you dont damage the pondweed or cause the liquid to overflow
what is the second step of the photosynthesis practical?
cut a piece of the pondweed, the pondweed should be 8cm long
what is the first step of the photosynthesis practical?
set up a boiling tube containing 45cm(3) of sodium hydrogen carbonate solution. Allow the tube to stand for a few minutes and shake to disperse any air bubbles that may have formed
what is the second stage of the menstrual cycle?
day 5-the uterus lining builds again, into a spongy layer of blood vessels ready to receive a fertilized egg until day 14
what is the 6th step of the negative feedback cycle?
communication system informs effectors
what are the endocrine glands?
found in different places (such as the pancreas)
- produces and secretes hormones which are passed into the blood
- consists of glands and organs
what is the third stage of the menstrual cycle?
day 14-the release of an mature egg (ovulation)
what problems does diabetes mellitus cause?
- blood glucose becomes dangerously high, damaging cells
- glucose cannot be stored as glucogen for later use
what does the pancreas do?
the pancreas senses change in blood glucose levels
-produces hormones (insulin) that enable glucoregluation
what is the 1st step of the hearts circulation of blood?
blood flows into the two atria from the vena cava and the pulmonary vein
what does FSH do?
causes the ovaries to mature an egg in a structure called a follicle
-stimulates the release of oestrogen
where is oestrogen produced?
ovaries
where is progesterone produced?
ovaries
what does LH stand for?
luteinizing hormone
what does LH do?
causes ovulation
what is a target organ?
a particular organ a hormone acts on