biology paper 1 Flashcards
What are all living things made off?
cells
What 2 things can an organism be?
Eukaryotes and Prokaryotes
What cells are Eukaryotic?
Animal and plant cells (more complex)
What cells are Prokaryotic?
Bacteria cells (simpler and single celled)
What is in the nucleus?
contains genetic material, that controls the cell’s activities. (DNA)
Job of cytoplasm?
a gel like substance where chemical reactions occur, (contains enzymes)
Job of cell membrane?
holds the cell together and controls what goes in and out.
Job of mitochondria?
respiration occurs here so transfer of energy can occur.
Job of ribosomes?
to help translation of genetic material in protein synthesis.
Job of cell wall?
support and strengthen cell (made of cellulose)
Job of a large vacuole?
contains cell sap and helps maintain the internal pressure.
Job of chloroplast?
photosynthesis occurs here so food can be made for the plant, it also contains chlorophyll
What do animal and plant cells have that bacteria cells do not?
A nucleus
Job of flagellum?
help rotate and move bacterium so that it can be moved away from harmful toxins or towards nutrients or oxygen
What is the function of the egg cell? and what it contains
Carry female DNA and to nourish the embryo in early stages. nutrients in the cytoplasm so the embryo can be fed, haploid nucleus and after fertilisation the membrane changes structure to stop more sperm getting in so offsprings end up with the right amount of DBA
What is the function of the sperm and what is in it?
Its function is to transport the male’s DNA to the females egg, it has a long tail to swim, lots of mitochondria in the centre to provide energy so it can swim far enough, an acrosome at the head so it can digest though the egg membrane and has a haploid nucleus.
What are ciliated Epithelial cells specialised for?
Moving materials
What two microscopes are used for studying?
Light and electron microscopes.
What microscopes is better and why a Light or Electron microscope?
An electron microscope while much more expensive is better as it has a higher resolution and magnification allowing you to see smaller things with more detail and structure.
How do you convert from millimetre downwards to a picometre and from a picometre upto a millimeter?
multiply by 1000 3 times to get to a picometre and picometre to millimetre dived by 1000 3 times
What are enzymes and what produce them?
Enzymes are catalysts made by living things
Why do enzymes have special shapes?
So they can catalyse certain reactions
What happens to the enzyme and substrate after a reaction?
The enzyme remains unchanged however the substrate splits in half and changes into two products off the reaction.
What happens if you change the temperature in an experiment?
the rate of an enzyme catalysed reaction changes
What happens to an enzyme if the reaction gets too hot?
the enzymes active site changes this means that the substrate can no longer fit causing the enzyme to become denatured.
What do all enzymes have?
An optimum temperature
What is an optimum temperature?
the temperature that the enzymes work best at
What can affect a reaction?
the temperature, ph and substrate concentration.
What is the normal optimum Ph?
pH7
What is the optimum Ph for pepsin?
pH2
What happens if you have a higher substrate concentration? Why?
You get a faster rate of reaction as it is more likely that the enzyme and substrate molecule will meet up.
What happens if you go above or below the optimum pH?
The reaction takes longer to work or won’t work at all.
What happens once you go above the optimum substrate concentration?
Once it goes above the optimum concentration the reaction levels out and will not go any faster as all sites are filled.
How do you test for Starch?
With iodine.
If starch is present colour changes from browny orange to a dark blue black colour.
What test do you use for Lipids?
The emulsion test
you shake substance with ethanol for 2 minutes
any lipids present will precipitate into a milky emulsion.
more lipids=more milky emulsion
How do you test for proteins?
Use the Biuret test,
add a few drops of potassium hydroxide to make an alkaline solution
the add copper II sulfate
if there is no protein the solution remains blue
f protein is present solution turns purple
What is diffusion?
The net overall movement of particles from an area of higher concentration to an area of lower concentration.
What is osmosis?
The movement of water molecules across a partially permeable membrane, froa region of high water concentration to low water concentration.
What does active transport work against?
A concentration gradient.
What is active transport?
The movement of particles across a membrane against a concentration gradient using the energy transferred during respiration.
What happens when there is a higher concentration of nutrients in the gut than the blood?
The nutrients will naturally diffuse into the blood.
What do chromosomes contain?
Genetic information.
What are the 4 stages of mitosis?
Prophase, Metaphase, Anaphase, Telophase
Prophase stage?
chromosomes condense and get shorter and fatter, membrane around nucleus breaks down and chromosomes lie free in the cytoplasm
Metaphase stage?
Chromosomes line up at the centre of the cell
Anaphase stage?
Cell fibres pull the chromosomes apart and 2 arms of each chromosome of to opposite ends of the cell
Telophase stage?
membranes form around each set of chromosomes these become the nuclei of 2 new cells, the nucleus divides
What happens at the end of mitosis?
2 new daughter cells are produced.
True or False are the daughter cells genetically identical haploid cells?
False they are two genetically identical diploid daughter cells.
What else are the cells identical to?
The parent cells.
What is cell differentation?
the process by which a cell changes to become specialised for a job.
How is cell division done?
Via mitosis
What is cell elongation?
The process by how plants grow, this makes cells bigger.
What sort of molecules are proteins, lipids and carbohydrates?
Big molecules
some food we eat have molecules to big to pass through walls in our digestives systems how do they get through?
Digestive enzymes break them down and make them smaller and more soluble molecules. These easily pass through and get absorbed into the bloodstream.
How do plants store energy?
In the form of starch.
What do plants do when they need energy?
They get enzymes to break down the starch into smaller molecules that acn be respired so energy can be transfered into cells.
What do carbohydrases do?
they convert carbohydrates into simple sugars.
What does proteases do?
They convert proteins into amino acids
what do Lipases do?
They convert lipids into glycerol and fatty acids.
How can carbohydrates be synthesised?
By joining simple sugars together
What is glycogen synthase?
An enzyme that joins together lots of chains of glucose molecules to make glycogen.
How are proteins made?
by joining amino acids together
How does all growth in animals occur?
Via cell division
How do plants tend to grow?
Via cell elongation
What controlls the rate at which cells divide?
the chemical instructions inside a cells gene.
What happens if a gene that controlls division alters?
The cell could start dividing uncontrollably.
What happens if a cell starts to divide uncontrollably?
a mass of abnormal cells will occur this is called a tumour.
What happens if a tumour invades and destroys surrounding tissues?
Cancer is formed
What is used to mointor weight and growth?
percentile charts
where are stem cells typically found?
in human embryos can be found in adult bone marrow too.
What does meristems contain?
Plant stem cells
What can we sometime cure sickle cell anaemia with?
we can use bone marrrow transplant. This contains new adult stem cells which will produce red blood cells.
What can we use stem cells for?
We can use them for replacing any cells that have been damaged by disease or injury. This is a big deal as it creates a potential for new cures.
What does the cerebrum do?
The largest part of the brain and has two parts the right hemisphere controls the muscles on the left hand side and the left hemispehre controls the muscles on the right hand side. different parts ave different possibilities this includes in movement, intelligence, memory, language as well as vision
What is the cerebellum responsible?
Muscle coordination and balance of the body.
Whats the job of the medulla oblongta?
It controls uncosncious activities like breathing and your heart rate.
Explain a CT scanner?
It uses x-rays to produce images of the brain and the scan shows the main structure of the brain but not the functions, However this changes when part of the brain is damaged the function of that part is able to be worked out