Biology - chemicals of life and human nutrition Flashcards
What chemical elements make up protein?
carbon, hydrogen, oxygen, nitrogen
What chemical elements make up carbohydrates?
carbon, hydrogen, oxygen
What chemical elements make up fats?
carbon, hydrogen, oxygen
How do small molecules join together to make big molecules?
the small molecules (monomers) come together to make big parts (polymers) through a process called polymerization e.g glucose molecules join to form starch
Explain the structure of protein
determined by the sequence of amino acids
Describe tests for starch
add iodine solution, Turns black-blue if positive, Turns yellow-brown negative
What is a balanced diet?
contains carbohydrates, proteins, fats, vitamins, minerals, fibre and water in the right proportions
What factors affect the dietary and energy needs of individuals?
age, weight, activity level
Describe the test for glucose
add Benedict’s solution,
Red - present
orange - moderate
yellow - low
green - trace
blue - none
describe the test for protein
add biuret solution,
positive is purple
Describe the role of water
a solvent in organisms
what does water help transport?
moves nutrients and oxygen through the bloodstream
How does water help excretion?
carries waste out through urine
What is the importance of carbohydrates?
Provides the body with energy
What are some principal sources of carbohydrates?
dairy products, fruit, vegetables, starchy foods
How does malnutrition affect the body in relation to starvation?
weight loss, muscle wasting, weak immune system
How does malnutrition affect the body in relation to coronary heart disease?
caused by unhealthy diets leading to the buildup of plaque in the arteries, which restricts blood flow and increases the risk of heart attacks.
Explain vitamin D deficiency
caused by not enough sun leading to weakened bones
Explain iron deficiencies
can be caused by blood loss and result in anemia
give 2 examples of protein malnutrition
- kwashiorkor
- marasmus
What are the main regions of the alimentary canal and associated organs.
mouth, esophagus, stomach, small intestion, large intestine, anus. associated with the liver, pancreas, and gallbladder
What happens in the moulth
Digestion begins
What happens in the esophagus?
Transports food to stomach
What happens in the stomach?
Breaks down food
What happens in the small intestine?
absorption of digested food
What happens in the large intestine?
absorbs water and forms waste to stool
What happens in the anus?
eliminates waste
What happens in the liver?
produces bile
What happens in the pancreas?
secretes digestive enzymes
What happens in the gallbladder?
stores bile
What is mechanical digestion?
physical breakdown of food
What is chemical digestion?
uses enzymes to break down large, insoluble molecules into smaller, soluble ones, allowing for nutrient absorption
What is absorption?
movement of small food molecules and ions through the wall of the intestine into the blood.
Is water absorbed in the intestines?
water is largely absorbed in the small intestine but also in the large intestine
What is the role of bile in neutralising?
it neutralizes the acidic gastric juice and food from the stomach providing a suitable pH
Outline another role of bile
Bile breaks down fats, increasing the surface area for enzymes to turn them into fatty acids and glycerol.
What is assimilation?
movement of digested food molecules into the cells
Describe the structure of the villus.
Villi is tiny finger like projections that increase the surface area of the small intestine and contain lymph capillaries down their centre. The job of the lymph capillaries is to absorb fatty acids into the lymph system from the small intestine as they are close to the surface area of the villi which leads to faster absorption
what is the significance of the villi and microvilli
increase of the surface area of the small intestine.
What does capillaries do in villi?
absorb nutrients
What does lacteals do in villi?
absorb fat
Define egestion
passing out of food that has not been digested as faeces
What is catalyst?
substance that increases the rate of a chemical reaction and is not changed by the reaction
What are enzymes?
proteins which function as biological catalysts
explain enzyme action
enzymes bind to the substrate at their active site, forming a complex that helps break down or build up molecules.
explain enzyme specificity
an enzyme only works with a specific substrate because their shapes fit together like a key in a lock
Explain the function and effects of HCl in gastric juice
lowers the pH, helps activate pepsin .
Investigate and explain the effects of temperature and pH on enzyme activity
Temperature increases enzyme activity by providing more kinetic energy for collisions, an effect is it can enzyme’s shape
What is the difference between deficiency and malnutrition?
Deficiency is to little of something
Malnutrition is not the right amount of something
What does bile help do?
Neutralise acids
What are the 3 graphs?
concentration, temperature, pH
What is a concentration graph?
- It means no more can be added
- looks like it remains constant
What is a temperature graph?
- Rise then drops in temperature
-Rise then drops the line
What is a pH graph?
- Denature of either side
- Looks like a mountain
describe the action of lipase
Lipase breaks down fat, into fatty acids and glycerol
What are the three main enzymes and what do they digest/ break down?
amylase - carbs , protease - protein , lipase - lipids (fats)
Where does amylase take place?
salivary glands and pancreas
Where does lipase take place?
small intestine
Where does protease take place?
stomach wall
What are 3 examples of carbohydrates?
pasta, potatoes, rice
What are 3 examples of protein?
nuts, meats, beans
What are 3 examples of fats/lipids?
cheese, oils, chocolate
What are faeces?
a combination of indigestible food, bacteria, and dead cells
How do you test for vitimin C?
DCPI, positive is colourless
What is the difference between chemical and physical digestion?
physical digestion prepares the food for further breakdown, chemical digestion actually breaks down the food so nutrients can be absorbed by the body.
How do you test for fats?
ethanol, milky colour positive
What is a monosaccharide?
simple sugar molecule, monomer of carbohydrates, soluble. fructose, and glucose
What is a disaccharide?
two monosaccharide’s, sweet and soluble. Sucrose, maltose, lactose
What is a polysaccharide?
starch-found in plant cells
cellulose- make up plant walls
glycogen-animal cells
insoluble and not sweet
What are the functions of carbohydrates?
broken down into glucose, which provides quick energy for cells
What smaller molecules does carbohydrates break down into?
monosaccharides, disaccharides, polysaccharides
What smaller molecules does lipids break down into?
3 fatty acids and glycerol
What are some polymers of lipids?
steroids, waxes,
What smaller molecules does protein break down into?
breaks down into amnio acid joined by a polypeptide chain
lipids function
Used in a cell to release energy
protein function
new cells for growth and repair, and transport molecules like haemoglobin
What are the 4 structures of protein?
primary -sequence of amino acids held together with peptide bonds
secondary - polypeptide chain folds into structures
tertiary - three-dimensional folding of a protein
quaternary -contain more than 2 tertiary units.
Why do we need a balanced diet?
To keep our alimentary canal working properly
What do carbohydrates do
quick energy
What do lipids do
store energy, insulate body, protect organs
What does protein do
growth, and repair
What does vitamin D do
Provides body with calcium
What does vitamin C do
supports immune system
What do minerals do?
strong bones
What does fibre do
aids digestions, prevents constipation
What is scurvy from
vitamin C deficiency
Why do you need iron
to make haemoglobin
What enzymes are released into the small intestine?
Amylase (breaks starch to maltose),
Protease (Breaks protein to amino acids or peptides)
Lipase ( breaks down fats to fatty acids and glycerol)
Bile ( breaks do fat and neutrilizes stomach acid)
What does amylase do?
Breaks down starch to maltose
What does maltase do?
Breaks down maltose to glucose
What does protease (pepsin&trypsin) do?
Breaks down proteins to peptides
What does peptidase do?
Breaks down peptides to amino acids
Where is peptidase?
small intestine
Where is trypsin?
pancreas
Where is pepsin?
stomach
maltose is broken down by______into_____
maltase, glucose
Sucrose is broken down by______into_____
sucrase, glucose
Lipids are broken down by______into_____
lipase, fatty acid and glycerol
Proteins are broken down by______into_____
protease, amino acids
Starch is broken down by ______into_____
Amylase, maltose
What is Enzyme denaturing
When the enzyme is exposed to high temperature or changes in pH, it changes shape, called a denature. This means the enzyme can not work properly as a catalyst
How does temperature effect enzyme activity?
protein denature at high temperatures, so the lock and key can no longer fit
How does pH affect enzyme activity?
causes the amino acid chain to coil or uncoil – become denatured, so lock and key can no longer fit
What is the active site?
where substrate molecules bind and undergo a chemical reaction.
What is amnio acids?
The building blocks of proteins
What does ingestion mean?
The process of taking food and liquids into the body.
What can vitamin D cause?
Rickets
What is a substrate?
The substance on which an enzyme acts.
