november mocks Flashcards
what is the role of enzymes?
biological catalysts in metabolic reactions
what happens to the rate of reactions when temperature increases up to the optimum? (enzymes)
the enzyme and substrate have more kinetic energy, so they have more frequent successful collisions, so there are more enzyme-substrate complexes formed, so rate of reaction increases
what happens to the rate of reaction when temperature increases past the optimum? (enzymes)
the active site changes shape so the substrate is no longer complimentary to the enzyme and it cannot fit into the active site anymore, so no enzyme-substrate complexes are formed, so rate of reaction decreases
describe the method for how enzyme activity is affected by changes in temperature?
- heat starch solution (in a test tube) to 10 degrees using a water bath
- add amylase to the solution then use a pipette to add a drop to the spotting tile
- immediately after, put a drop of iodine to the starch solution
- add another drop after 30 seconds to the next spotting tile and add iodine solution
- repeat every 30 seconds until the iodine solution stays orange
- repeat all 5 steps for 20 30, 40, 50, 60 degrees
how do pH levels affect enzyme activity?
as the pH increases up to the optimum, the enzyme’s active site becomes more complimentary to it’s substrate, so enzyme activity increases. after it reaches the optimum, the active site changes shape and so the enzyme denatures so enzyme activity decreases/stops
what is diffusion?
random movement of particles from high concentration to low concentration
what is osmosis
net diffusion of free water molecules from an area of high water potential to low water potential across a semi-permeable membrane
what is active transport?
the movement of molecules from an area of low concentration to high concentration using ATP
how does SA:V affect the rate of diffusion?
the smaller the sa:v is, the higher the rate of diffusion
how does distance affect diffusion?
the further the distance, the lower the rate of diffusion
how does concentration gradient affect diffusion?
the higher the concentration gradient, the higher the rate of diffusion
how do you investigate osmosis in a living system?
- use a cork borer to cut equal cylinders in a potato
- cut the cylinders the same length (about 3cm) - have five
- measure and record the mass of each
- measure out 10cm^3 of 0M, 2.5M, 5M, 7.5M, 1M sucrose solution into 5 different test tubes
- add one potato cylinder (of known mass) into each tube
- leave for 30 minutes
- take out each potato and gently dry them by tapping them with a paper towel then weigh them and record the new mass for each
how do you investigate osmosis in a non-living system?
connect a visking tube to a capillary tube, and fill the visking tube with sucrose solution and put into a beaker with 20 cm^3 of water. leave for 30 mins, then measure the volume of water. repeat with different concentrations of sucrose solution
how do you investigate diffusion in non-living systems?
put potassium permanganate crystals in a beaker of water. observe after 15 minutes, then observe after 1 hour
what are organelles?
small structures in the cell with a specific function
what are cells?
smallest functional unit of life, contain organelles to carry out specific function
what are tissues?
a group of similar cells, working together to carry out the same function
what are organs?
made up of several different tissues working together to carry out a more complex function
what are organ systems?
made up of several different organs working together to carry out a complex function essential for life
what is in an animal cell?
a nucleus, mitochondria, cytoplasm, cell membrane, ribosomes
what is in a plant cell?
a nucleus, mitochondria, cytoplasm, cell membrane, cell wall, ribosomes, chloroplasts, vacuole
what is the function of a nucleus?
controls the activity of the cell (by making proteins), contains the chromosomes
what is the function of a cell membrane?
controls what goes in and out of the cell (selectively-permeable)
what is the function of the cytoplasm?
jelly-like liquid where chemical reactions occurred
what is the function of the mitochondria?
site of aerobic respiration
what is the function of the ribosomes?
protein synthesis from amino acids
what is the function of the chloroplasts?
site of photosynthesis
what is the function of cell walls?
keeps the shape of cell, prevents the cell from bursting
what is the function of the vacuole?
contains cell sap, stores dissolved sugars, mineral ions, and other substances
what is the function of the mouth?
mechanical digestion; increased sa:v, chemical digestion; salivary amylase breaks down starch into maltose, food is shaped into bolus
what is the function of the oesophagus?
connects mouth to stomach, peristalsis to push bolus down to stomach (mechanical digestion)
what is the function of the stomach?
chemical digestion: pepsin from stomach walls to break down proteins into peptides, mechanical digestion by muscle churning, stomach aid lowers pH for pepsin and sterilises food
what is the function of the duodenum?
chemical digestion - contains many enzymes (amylase, lipase, protease)
what is the function of the ilieum?
chemical digestion - enzymes break down food
villi and microvilli to absorb nutrients
what is the function of the colon?
reabsorbing water to make faeces
what is the function of the rectum?
egestion
what is the function of the pancreas?
secretes enzymes into the stomach and small intestine
what enzymes are there in the mouth and what do they do?
salivary amylase
starch –> maltose
what enzymes are there in the stomach and what do they do?
pepsin
proteins –> peptides
what enzymes are there in the duodenum and what do they do?
pancreatic amylase
starch –> maltose
trypsin
peptides –> amino acids
pancreatic lipase
lipids —> fatty acids and glycerol
maltase (from glands in the walls)
maltose —> glucose
what enzymes are produced in the pancreas?
pancreatic amylase, trypsin, pancreatic lipase
what kind of enzymes are in the ileum?
maltase
where is bile produced?
liver
where is bile stored?
gall bladder
what is the function of bile?
emulsifies lipids and neutralises stomach acid
what is in stomach acid?
hydrochloric acid and pepsin
how is the small intestine adapted for absorption?
thin cell walls -> shortens diffusion distance
large surface area to volume ratio from villi and microvilli
large network of capillaries for maintaining the concentration gradient
what process produces ATP?
respiration
what is the difference between aerobic and anaerobic?
aerobic needs oxygen and produces more ATP
what is the word equation for aerobic respiration?
glucose + oxygen –> water + carbon dioxide (+ATP)