Grade 10 Biology TEST on Molecular Biology and Human nutrition Flashcards
4 Main Biological Molecules
Carbohydrates (energy containing molecules)
Proteins (energy containing molecules)
Lipids (energy containing molecules)
Nucleic acid (DNA, RNA)
Carbohydrates
Monosaccharides: ex - glucose
Disaccharides: ex - sucrose
Polysaccharides: ex - starch
Elements of Carbohydrates
Carbon (1), Hydrogen (2), Oxygen (1)
- Most carbohydrates have this ratio.
Glucose structure
6 siding:
- carbon atom: 4 bonds
- oxygen atom: 2 bonds
- hydrogen atom: 1 bond
- nitrogen atom: 3 bonds
*go to notebook
Starch
Carbohydrate made by plants (stored in the chloroplast) for energy storage
Glycogen
Carbohydrate made by animals for energy storage
Element in protein but not carbs or fats.
Nitrogen and sulfur
Amino acids
Small molecules to join protein molecules together.
Protein examples
Keratin, collagen and elastin
What determines the number of covalent bonds that an atom can form?
The number of electrons required to fill the valence shell.
Monosaccharides
(single sugars)
- Glucose (C6H1206)
- Fructose (C6H1206)
- Galactose (C6H1206)
- Ribose (Help us produce RNA and DNA)
- Deoxyribose (Help us produce RNA and DNA)
Most important monosaccharide
6CO2 + 6H2O → C6H12O6 + 6O2
Photosynthesis
How do we produce the disaccharide Maltose by joining two glucoses?
*go to notebook
What have we done?
- Condensation reaction
- A water molecule is produced
- Glucose + Glucose –> Maltose + Water
- An enzyme is required
- An ATP molecule is required
What are other disaccharides?
- Glucose + Fructose –> Sucrose
- Glucose + Galactose –> Lactose
How do we make a polysaccharide?
Continue to add glucoses by conducting additional condensation reactions.
*go to notebook
Starch to Glycogen
Eat starch (pasta) – digest – glucose in blood – excess glucose – converted to glycogen (by the liver and the muscles, over time glycogen is converted back to glucose).
- glucose is used by cells to make ATP.
Proteins
Carbon, hydrogen, oxygen, nitrogen, sulfur (CHONS)
- proteins are long single-chained polymers of amino acids.
- allow your body to develop and grow by repaired body cells and works as structural support
What is the structure of the amino acid?
*go to notebook
20 different types of amino acids.
Standard structure: carboxyl group, amino group and central C with H.
- R group/side chain/radical group
- Amino (NH2 - Ammonia) group
- Carboxyl group/COOH group/organic acid group
Why is it called carboxyl group?
All organic products have carbon, oxygen and hydrogen.
Why is it called organic ACID group?
H separates from the O leaving an H+ and 0- (disassociation)
Which feature is different from one amino acid to the next?
The R group (20 different R groups)
In what ways can R groups differ?
These factors determine the structure (determines/affects its function) of the protein (rich amino acids are present in the proteins and the specific sequence of the amino acid in the chain).
- size (small or big)
- hydrophobic (water hating - repels: less soluble in water)
- hydrophilic (water loving: more soluble in water)
- Acidic or alkaline
- positively or negatively charged
- contain sulfur or not (2 of 20 do not)
Connecting two amino acids together
*go to notebook
creates a peptide bond
- when we produce protein we are connecting amino acids
Two amino acids are joined by a covalent bond to form a dipeptide.
Characteristics of connecting two amino acids together
- condensation reaction
- water is produced
- amino acid + amino acid –> dipeptide + water
- enzyme (in the ribosome) is required
- ATP is required
Mouth, oesophagus and stomach
when food is chewed, the tongue mixes the food with saliva, which contains mucus (a slimy substance that lubricates the passage of the food bolus down the throat). when food is swallowed, it squeezes pst your epiglottis into your oesophagus.
Stomach digestive juice
gastric juice
- protease produced by the the walls of the stomach is called pepsin.
- starts the digestion of proteins to smaller molecules called polypeptides.
Amylase
breaks down starches and carbohydrates into sugars.
Protease
breaks down proteins into amino acids.
Lipase
breaks down lipids, fats and oils, into glycerol and fatty acids.
Functions of proteins
- movement (muscle): actin and myosin
- transports: hemoglobin transports O2
- catalyzing chemical reactions: enzymes (catalase)
- structure: keratin and collagen
- defense (against pathogens): antibodies
- communication (within the body): hormones and neurotransmitters (there are some that are not proteins)
Lipids
carbon, hydrogen, oxygen (CHO)
- ration: oxygen is much less than in carbohydrates.
- less soluble in water than carbohydrates
- contain more energy than carbohydrates or lipids (37 kJ/g)
Energy content
- lipids: about 37 kJ/g
- carbohydrates: about 19 kJ/g
- proteins: about 19 kJ/g
Structure of the triglyceride
(one of the most common lipids)
- triglyceride is a glycerol molecule connected to three fatty acid molecules.
*go to notebook
glycerol structure
- glycerol head
- fatty acid tails
fatty acid structure (has COOH group)
- carboxyl group (amino acids have it too)
- Hydro-carbon chain (usually between 10-30 carbons)
Saturated (fatty acid)
mostly made by animals
solid at room temperature
- milk fat to make butter
- lard (animal fat)
- bacon
Unsaturated (fatty acid)
made by plants
structure
- bend/kink from double covalent bond
- now we can only add one hydrogen
liquid at room temperature
one or more carbon = carbon double bonds
- there is a bend at each double bond
- the unsaturated has fewer hydrogen than the saturated fatty acids.
Condensation
- loss of an -OH from one molecule and an -H from another
- forms H20
- to break bond, water is added in a reaction called Hydrolysis
Peptide bond
bond between two amino acids in a dipeptide
Digestion
necessary because it allows humans to breakdown food and turn it into energy
Enzymes for digestion
- starch: amylase enzyme –> glucose
- protein: protease enzyme –> amino acids
- fat: lipase enzymes –> fatty acids and glycerol
Mechanical digestion
the physical breakdown of food particles to increase the surface area
Chemical digestion
the breakdown of large insoluble food molecules into smaller, water-soluble molecules by the actions of enzymes
Nutrients for the body
- carbohydrates: provide a source of energy
- proteins: allows your body to develop and grow
- fats: long term energy store
- vitamins and minerals: to avoid deficiency diseases
- fibre: lowers concentration of cholesterol
Deficiency disease
a medical condition caused by a lack of essential nutrients like vitamins or minerals in a person’s diet over a long period of time
What are the differences among the polysaccharides starch, glycogen, and cellulose?
Starch and glycogen are made up of 𝜶-glucose subunits, whereas cellulose is made up of 𝛃-glucose subunits.
What are the main nutrient types in human nutrition?
Carbohydrates, lipids, proteins, vitamins, minerals, water, fiber.
Carbohydrates function and examples
fiber, starches and sugars — are essential food nutrients. Your body turns carbs into glucose (blood sugar) to give you the energy you need to function.
Lipids function and examples
part of your cell membranes and help control what goes in and out of your cells. They help with moving and storing energy, absorbing vitamins and making hormones.
foods: primarily oils (liquid) and fats (solid)
Proteins function and examples
growth and repair of body cells. Food sources of protein include meat, fish, dairy, lentils, beans, and tofu.
Condensation Reaction
two monomers are covalently bonded together and a water molecule is produced. In a condensation reaction, two smaller molecules (monomers) react to form a larger molecule (polymer) by covalently bonding together.
What are the 5 components (phases) of human nutrition?
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
Ingestion
taking food into the body
Digestion
breaking down large nutrient molecules into smaller nutrient molecules.
Absorption
Movement of the small nutrient molecules form the lumen of the gut into the blood.
Lumen
the volume/space inside an organ
Gut
digestive tract
Assimilation
the movement of small nutrient molecules from the blood into the body’s cells
Egestion
the elimination of wastes and indigestible material
Digestive tract organs
Mouth
Throat
Esophagus
Stomach
Small intestine (coiled up/5-6m)
Large intestine
Rectum (feces are stored)
Anus
Large intestine
chyme goes through it
Associated organs
salivary glands
liver
gall bladder
pancreas
salivary glands
saliva lubricates food and contains enzymes
liver
right side of the body
gall bladder
gland next to the liver
pancreas
right behind the stomach
How does unsaturated fat affect our health?
Triglyceride from unsaturated fatty acids.
- not cubic, irregular structure
do not fit together
Do not form deposits/plaques within arteries
- lowers risk of CHD
how does saturated fat affect our health?
Triglyceride from saturated fatty acids.
- cubic, regular structure
easily fit together
Easily form deposits/plaques within arteries
- can cause a block
- high risk of CHD (coronary heart disease)
may contribute to hardening of the arteries or thickening of the artery walls (arteriosclerosis)
Nutrients that are small molecules
Do not have to be digested and can be absorbed quickly.
- water (H20)
- Glucose and fructose
- Ethanol (alcohol)
Must be digested
Polysaccharides
Proteins
Polysaccharide digestion step one
starch + water –> maltose
- amylase enzyme
reaction begins in the mouth with salivary amylase (optimum pH 7)
stops in the stomach (ph 2 so it denatures)
resumes in small intestine
- amylase is produced and secreted by the pancreas (through tube called pancreatic duct)
- starch will most be broken down to maltose in the small intestine.
Polysaccharide digestion step two
maltose + water –> glucose
- maltase enzyme
occurs in the small intestine (at pH 7)
Protein digestion step one
large protein + water –> small polypeptides
- pepsin enzyme
Protein digestion step two
smaller polypeptides + water –> single amino acids
- protease enzyme
- occurs in the small intestine (pH 7)
- the protease is produced and secreted by the pancreas
Hydrolysis
reverse of condensation reaction
- reaction with water to break a bond
a larger molecule forms two (or more) smaller molecules and water is consumed as a reactant
Pepsin
produced and secreted by the stomach
- optimum pH 2
- contains HCl
Absorption (of small nutrient molecules)
- occurs in the small intestine
- Villus provides a large surface area for absorption.
How is the small intestine adapted to maximize absorption of nutrients?
The lining is highly folded to form villi which increase the surface area to help with absorption.
