B2b Flashcards
What are enzymes?
Enzymes are biological catalysts produced by living things
What could increasing the temperature do in some reactions?
Speed up unwanted reactions, not just the useful ones
What’s a catalyst?
A substance that increases the speed of a reaction, without being changed or used up in the reaction
What are proteins made up of?
Chains of amino acids
What does a substance have to do for an enzyme to work?
Fit the special shape
Enzymes need the right what to work?
Temperature and pH
In humans, what’s the temperature that enzymes work at?
Around 37 degrees
What pH do most enzymes work at?
pH 7
What enzyme works at pH 2?
Pepsin, an enzyme in the stomach
What do digestive enzymes do?
Break down big molecules into smaller ones
What does amylase do and where is it found?
Breaks down starch into sugars, found in salivary glands, the pancreas and small intestine
What does protease do and where is it found?
Breaks down proteins to amino acids, found in the stomach, pancreas, small intestine
What does lipase do and where is it found?
Breaks down lipids into glycerol and fatty acids, found in the pancreas and small intestine
What does bile do?
Neutralises tthe stomach acid and emulsifies fats
Give the name of each different place in the digestive system and how it’s catalysed by each enzyme
Salivary glands make amylase
Liver: Bile is produced here, it neutralises stomach acid and emulsifies fats
Stomach: Pummels food with walls, produces pepsin (protease enzymes) and produces HCl
Gall bladder: Where bile is stored
Pancreas: produces protease, amylase and lipase
Small intestine: Produces protease, amylase and lipase also. Digested food is absorbed into the blood here
Large intestine: Where excess water is absorbed from the food
What is respiration?
The process of releasing energy from glucose which goes on in every cell
What’s the equation for aerobic respiration?
Glucose + oxygen → carbon dioxide + water + energy
What is the energy released in respiration used for?
- Build up larger molecules from smaller ones (proteins/amino acids)
- In animals- allows muscles to contract
- In mammals and birds - energy is used to maintain body temperature
- In plants- used to build sugars, nitrates and other nutrients which are built up into proteins
When you exercise what do your muscles need?
More glucose and oxygen to work
What needs to be removed from the muscles during exercise?
Carbon dioxide
How does your body react to exercise to remove CO2 and provide oxygen and glucose?
- Breathing rate increases: meets the demand for extra oxygen
- Heart rate increases: blood pumps quicker to get oxygen and glucose to working muscles
How is glycogen used in exercise?
When muscles use up glucose rapidly, some stored glycogen is converted into glucose to provide energy
What is anaerobic respiration?
The incomplete break down of glucose which produces lactic acid- ‘without oxygen’
What’s the word equation for anaerobic respiration?
Glucose → Energy + lactic acid
Why isn’t anaerobic respiration the best way to convert glucose into energy?
Lactic acid builds up which becomes painful
What’s the disadvantage of anaerobic respiration?
It doesn’t release enough energy
What’s the advantage of anaerobic respiration?
You can keep using your muscles for longer
What does anaerobic respiration lead to?
Oxygen debt
What’s oxygen debt?
When you have to repay the oxygen that didn’t get to your muscles in time
How does your body react to oxygen debt?
You breathe heavily to get oxygen to the blood
What household items are enzymes used in?
- Biological detergents
- Baby foods
What are the advantages of using enzymes in the industry?
- They’re specific- they catalyse 1 reaction
- Using lower temp&pressure = lower cost
- Enzymes work for a long time so can be continually used
- They’re biodegradable- less environmental pollution
What are the disadvantages of using enzymes in the industry?
- Some people can develop allergies to them
- Enzymes can be denatured by a small increase in temperature
- They are susceptible to poisons
- Contamination of the enzyme can affect the reaction
What does DNA stand for?
Deoxyribonucleic acid
Where’s DNA found?
In the nucleus of animal and plant cells in long molecules called chromosomes
What is a gene and what does it contain?
A section of DNA, it contains instructions to make a specific protein
How do cells make proteins?
By putting together a chain of amino acids
What is DNA fingerprinting a way of?
Cutting up a person’s DNA into small sections and seperating them
What’s DNA fingerprinting used in?
Forensic science: Can be taken from a crime scene and compared with a suspect
Paternity tests: to see if a man is the father of a particular child
What would be the advantages of having a genetic database?
Criminals can be caught
What would be the disadvantages of having a genetic database?
Invasion of privacy
Data might not be safe
False positives can occur if errors are made in the procedure
What does mitosis make?
New cells for growth and repair
What is mitosis?
When cells divide to make 2 cells, identical to the original cell- with the same number of chromosomes
What’s meiosis?
Cell division that’s used to produce male and female gametes
What does meiosis produce?
Cells with half the number of normal chromosomes
What type of reproduction uses mitosis?
Asexual
What type of reproduction uses meiosis?
Sexual
After two gametes join at fertilisation, the cell grows by repeatedly dividing by?
Mitosis
What are stem cells?
Cells that can turn into any type of cell- undifferentiated
Where are stem cells found?
In early embryos, bone marrow and the umbilical chord
How are stem cells used in medicine?
- To cure blood diseases- bone marrow transplant
- To replace faulty cells- embryonic stem cells
- Heart muscle cells
- Insulin producing cells- people who are paralysed
- To get cultures of one specific type of cell
Why are people against using stem cells?
- People feel that human embryos shouldn’t be used- potential life
- Some think scientists should develop new resources to get stem cells from
Why are people for using stem cells?
- Some people think curing people that exist is more important than the rights of embryos
- Embryos used are often unwanted and destroyed- good to use them
How many pairs of matched chromosomes are there?
22
What are the 23rd pair of chromosomes and what do they determine?
Either XX or XY - determine your gender
Which pair of chromosomes belong to which gender (XX/XY)?
XX = female XY = male
What happens to the chromosomes when sperm is made?
The X and Y chromosomes are drawn apart- there’s a 50% chance each sperm cell gets an X-chromosome and a 50% chance it gets a Y-chromosome
