Biology Final Ka Year 10 Flashcards
What are eukaryotic cells and what are examples of them?
Complex cells.
Animal and plant cells
What are prokaryotic cells and what is an example of one?
Smaller and simpler cells.
E.g. Bacteria
Label animal cell diagram on sheet
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Label plant cell diagram on sheet
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Label bacterial cell diagram on sheet
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What is the equation for magnification?
Magnification = image size ÷ real size
How do you convert micrometers into mm?
Divide by 1000
What makes chemical reactions work?
Enzymes
What is a catalyst?
A substance which increases the speed of the reaction without being changed or used up in the reaction
How could you speed up a chemical reaction?
Raise the temperature
Why do living things produce enzymes?
Living things produce enzymes that act as biological catalysts which reduce the need for big temperatures and we only have enzymes to speed up useful chemical reactions in the body
What are proteins? What are they made up of?
They are large proteins which are made up of chains of amino acids.
What do all enzymes have?
An active site with a unique shape that fits onto the substances involved in a reaction
What happens if the substrate doesn’t match the enzymes active site?
The reaction won’t be catalysed because enzymes only catalyse one specific reaction
Label enzyme model on sheet
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What happens if enzymes get too hot?
The bonds break and change shape so they can’t fit into their active site any more. The enzyme becomes denatured
What does the enzyme amylase do?
Catalyses the break down of starch to maltose.
What will happen to iodine solution if starch is present?
It will change from browny-orange to blue-black
How can you investigate how pH affects amylase activity?
- put drops of iodine into the wells of a sporting tile
- put a tripod over a Bunsen burner and put a beaker of water on top and heat until it’s 35°C using a thermometer
- add 1cm³ of a buffer solution with a pH of 5 to a boiling tube and place in water
- wait for 5 mins when add 5cm³ of a starch solution to the tube
- mix the contents and start a stop watch and measure how long it takes for the amylase to break down all of the starch
- place a sample from the tube every 30 secs and put a drop into a well
- when the solution remains brown starch is no longer present
What is a enzymes optimum temperature?
40°C
What are the microorganisms that cause disease?
Pathogens, they can be: bacteria, viruses, fungi, Protists
How do bacteria make someone ill?
Thy release toxins into their host making them ill
How do viruses make a person ill?
They attach to a cell, injects DNA, DNA replicates using host, new vital DNA is released
Explain what a pathogen does when it enters the body.
- enters body
- reproduces rapidly
- bacteria make harmful toxins, viruses damage cells
- symptoms develop
How can diseases be spread?
- droplet infection
- touching
- break in the skin
- via animal bite
- vector organism
- sexually transmitted
- food and drink
How can u stop the spread of disease?
- clean water supplies
- sewage treatment
- hand washing in hospitals
- personal hygiene
- food storage
- isolation
- disinfectants
What conditions do microbes need to work?
- food and oxygen
- warmth
- moisture
- correct pH
- correct salt concentration
How can we prevent microbes growing?
- freezing
- canning
- pickling
- drying
- salting
- pasteurisation
What does aseptic mean?
Without microorganisms
Why might you use the aseptic technique?
Any unwanted bacteria will not contaminate your experiment.
Any bacteria from your experiment will not escape the plate
What does the body do to protect you from disease?
- Skin- acts as a barrier
- Scabs- clots form to seal wounds
- Breathing- mucus traps pathogens and cilia helps remove it
- stomach- acid destroys food pathogens
- enzymes - special enzymes in urine, tears and saliva kill bacteria
- white blood cells - destroy pathogens that enter the blood
How do white blood cells destroy microorganisms?
They ingest them
How do white blood cells target particular bacteria or viruses?
They produce unique antibodies for each type of bacteria or virus. Once they have produced antibodies for then, they can produce them again rapidly if the pathogen enters the body again
What are antitoxins and what produces them?
They are made by the white blood cells and neutralise the toxins made by bacteria that make you ill
What happens if antibodies or antitoxins are not made fast enough?
They overwhelm the body so you get ill or die
How do antibodies prevent disease?
Because they are ready in your body for the next time you get a disease you’ve already had so they can be produced fast enough for symptoms to not occur
How do vaccines work?
You are injected with a dead or harmless version of a pathogen. Your white blood cells produce antibodies. If you come into contact with the real version of the pathogen you white blood cells can respond more quickly. Infection is prevented
What are live altered pathogens?
Live altered pathogens are most effective as they can still reproduce and so trigger a full immune response
What are dead pathogens?
Dead pathogens don’t trigger a big enough initial response and so a second dose is needed.
What is active immunity?
Which blood cells which produce a specific antibody have been produced. Provides permanent immunity
What is passive immunity?
Antibodies are directly given. Only provide temporary immunity.
What is herd immunity theory?
The more people in a population that are vaccinated then the more likely you are to prevent infection of the non vaccinated
What do antibiotics do?
Help to cure bacterial diseases by killing infective bacteria inside the body by destroying bacterial cell walls that kill the bacteria
What can antibiotics not kill?
Viral pathogens which live and reproduce inside the cells
What do antiseptics and disinfectants do?
Kill bacteria outside of the body by are to poisonous to be taken internally
Why is it hard to design vaccines against viruses?
Because they are tolerant of mutations
What must drugs be?
Effective - prevent or cure the target disease or make you feel better
Safe - must not be too toxic or have very bad side effects
Stable - possible to store for a period of time