Save
Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't know
Remaining cards (0)
Know
0:00
share
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

gcse science B4 - G

specific for ocr gateway additonal science B.

QuestionAnswer
what does detritus mean? remains of dead and decaying plants and animals
what are detritivores? animals which depend on detritus for their food
examples of detritivores? earthworms, maggots, woodlice
what do detritivores do? speed up decay as they break the detritus down into smaller pieces, which increases the surface area
why are detritivores important? they recycle chemicals from dead plants and animals
what is another method of using decay? for compost
what conditions speed up the composting process? -warmth -moisture -good aeration (to allow oxygen in)
what happens inside a compost bin? microorganisms respire, which give off heat and warms up the compost, which speeds up decay
what does decay depend on? enzyme action - conditions that speed up enzyme action also speed up decay
what is the optimum temperature for bacteria? 37
what is the optimum temperature for fungi? 25
what are the two types of bacteria? aerobic and anaerobic
why do aerobic bacteria break down dead detritus quickly? because they produce oxygen, which speeds up decay
why do anaerobic bacteria break down dead detritus slowly? because they produce acid conditions, which slows down decay
what is a saprophyte? a fungus that feeds off dead and decaying materials
what happens to the saprophyte's digestive enzymes? released on to the food and break it down into simple soluble substances so the digested food is absorbed easily
what are the 5 ways to preserve food? canning, cooking, vinegar, drying, freezing, adding sugar or salt
how does cooking work? kills bacteria. food poisoning is caused by food being undercooked
how does canning work? killheats food before being canned to kill the bacteria. then sealed in a can to stop any bacteria getting ins bacteriA
how does vinegar work? it's an acid. very few bacteria can grow in acid conditions.
examples of food preserved in vinegar? pickled eggs, chutney
how does drying work? bacteria and fungi can't grow without water
examples of food preserved by drying? cereals
how does freezing work? kills bacteria or slows their growth
how does adding sugar or salt work? kills some bacteria and fungi and stops the growth of others
Created by: jirwin
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards