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Flashcards in biggies Deck (5)
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1
Q

what are the factors that affect enzyme activity and explain them

A

1) temperature - at lower temperature molecules move slowly. so substrate molecules take longer to fit into and react in the active site, at optimum temperature they work at their fastest rate, at high temperatures the active site changes shape and cant hold the substrate and the reaction goes slowly
2) adding more substrate increases the rate of reaction, adding too much substrate would take little effect as the active site of every enzyme molecule is busy. the chart plateus off
3) the enzyme works fastest at its optimum pH, as you go further from the optimum pH, the rate of reaction is slower. changing the pH can change the shape of the enzymes active site, and so change its ability to bond with the substrate

2
Q

Demonstrate an understanding that enzymes catalyse chemical reactions occurring inside and outside living cells

A

a) DNA replication
1) one enzyme catalyses the splitting apart of the two DNA strands
2) a different enzyme catalyses the jining together of bases to make new strands
b) protein synthesis
1) each reaction during protein synthesis is controlled by a different enzyme
c) digestion
1) are secreted into the alimentary canal to break down the large molecules in our food into much smaller ones. the small food molecules can then be absorbed into the body.

3
Q

explain the process of transcription

A

transcription

1) a section of DNA is unwound and the two strands separate
2) free complementary bases pair with open bases on one DNA strand. the free bases are joined together to make a strand of complementary mRNA

4
Q

Describe the functions of the parts of the digestive system,

A

a) mouth - food enters the body, chewing breaks up food and mixes it with enzymes to start digestion
b) oesophagus - carries food from mouth to stomach
c) stomach - acid and enzymes added, stomach contents mixed by churning of muscular wall
d) small and large intestines - digestion of food by enzymes completed, food molecules are absorbed into the blood, water absorbed form digested food
e) pancreas - produces enzymes that are released into the small intestine
f) liver - produces bile, which helps in digestion of fats in small intestine, converts food molecules absorbed from small intestine into other molecules
g) gall bladder - bile from the liver is stored until needed in the small intestine.

5
Q

explain the process of translation

A

translation

1) ribosome move along the mRNA in this direction reading one triplet of bases(codon) at a time
2) tRNA molecules bring amino acids to the ribosome. the amino acid attached to each tRNA molecule depends on the order of bases in the tRNA
3) complementary bases of tRNA pair with the bases on the mRNA strand
4) amino acids that are close together are joined to make an amino acid chain (a polypeptide)
5) tRNA free to collect another amino acid