Carbohydrates,lipids Flashcards
What elements do carbohydrates contain?
C, H, O
The general formula for carbohydrates
Cx(H20)y
Other names for carbohydrates
Saccharides, sugars
What is a single sugar unit called?
Monosaccharide’s
Examples of monosaccharides
Glucose
Fructose
Ribose
Carbohydrates are the…
Source of all energy
Where does glucose come from?
Comes from the sun- plants photosynthesise
Formula for glucose
C6 H12 06
What is a disaccharide?
2 monosaccharide’s joined together
Example of a disaccharide?
Lactose, sucrose
What is a polysaccharide?
When 2 or more monosaccharide’s join together to form a polymer
Examples of a polyssccharide?
Glycogen, starch and cellulose
What are the main monomers of a biologically important large carbohydrate?
Glucose
Describe glucose?
Glucose is a monosaccharide built of six carbons therefore a hexose monosaccharide
Which way are the carbons numbered in a molecular structure diagram?
Clockwise
What is the difference between alpha glucose and beta glucose?
The OH group on carbon 1 is in the opposite position in beta, its been flipped
Glucose molecules are…. +- and soluble in….
Polar
water
Why are glucose molecules soluble in water and polar
This is from the hydrogen bonds that form in the OH group and water molecules.
Why is it important glucose dissolves in water?
It is able to dissolve in the cytosol and be transported to where it is needed
How do 2 glucose molecule join together
When the two alpha glucose molecules are side by side the two hydroxyl groups interact. This happens when bonds are broken and new bonds reform at carbons 1 and 4 on the glucose molecules- molecules now joined and created maltose
What is removed when two alpha glucose molecules join together?
Two hydrogen atoms and an oxygen atom are removed from the glucose monomers and join to form water.
What reaction takes place when two alpha glucoses join together?
condensation reaction as water is gained
What covalent bond is formed between two glucose molecules?
Glycosidic bond
What is a condensation reaction?
Where a water molecule is formed from one of the products reactions
What glycosidic bond does two glucose molecules make?1
1,4 glycosidic bond
What is maltose an example of?
Disaccharide
Name some hexose monosaccharides?
Fructose
galactose
Describe fructose
Found in fruits, sweeter than glucose
what does
fructose+ glucose make
Sucrose- cane sugar
What does galactose +glucose make
Lactose
Where is lactose found?
In milk and milk products
Fructose, glucose and galactose
Sweetest to sweet
Fructose
Glucose
galactose
What are pentose monosaccharides
Sugars that contain 5 carbon atoms.
Name two important pentose sugars
Ribose in RNA nucleotides
Deoxyribose in DNA nucleotides
What is starch made up of?
Many alpha glucose molecules that are joined together by glycosidic bonds to form the polysaccharide- starch
Where is glucose made and what is it stored as?
In plants as starch
Name two polysaccharides found in starch?
Amylose
Amylopectin
Describe amylose
Formed by alpha glucose molecules joined together by 1-4 glycosidic bond
Long chains that twists to form a helix which is stablised by hydrogen bonds.
Therefore compact, less soluble
Describe Amylopectin
Made from a 1,4 glycosidic bond between alpha molecules but glycosidic bonds also seen on 1,6 carbons on two glucose molecules
Branching structure
insoluble
What is the energy storage molecule in starch?
Glycogen
Describe glycogen
Branches = more compact and less space is needed for storing it, which is important for mobile animals
compact
insoluble
What make glycogen compact?
The coiling of the polysaccharides
What benefit does glycogen have that speeds up adding or removal of molecules?
The free ends allows for molecules to be added, which speeds process up
Similarities of glycogen and amylopectin
Insoluble
branched
compact
What is glucose stored as in plants?
Starch
What is glucose stored as in animals/fungi?
Glycogen
Why do animals need glucose?
For respiration
How is glucose released after it has been stored as starch?
Undergoes hydrolysis reactions
What does hydrolysis require
Water
Beta glucose molecules are unable to join. Whys this?
The 1 and 4 carbon are too far from eachother to react
What do beta glucose molecules doso they can react?
Turns the alternative beta molecule upside down
Limitation from 2 beta glucose molecules joining together?
They are unable to coil = form straight chain
What straight chain does two beta glucose molecules make?
Cellulose
What bonds do hydrogen bonds make when forming cellulose
Microfibrils
What sugars are reducing sugars
Disaccharides and monosaccharide’s
What does the term ‘reducing sugar’ mean?
Means it can donate electrons or reduce another chemical/molecule
What chemical test is used for a reducing sugar?
Benedicts test
How is the benedicts test carried out?
- Place sample in boiling tube (grind if not liquid)
- Add an equal amount of benedicts regeant
- Heat mixture gently in boiling water for 5 minutes
- if reducing sugar turns red
How do reducing sugars react with benedicts regeant?
reducing sugars react with copper ions in the benedicts reagent.
addition of electrons to the blue Cu+ ions, reducing them to red Cu+ ions.
What colour indicates a reducing sugar in the benedicts test?
Red precipitate
What doesn’t react in the benedicts test?
reducing sugars- stays blue
What is a common non reducing sugar?
Sucrose
How do they get sucrose to be able to undergoes the benedicts test?
boil with hydrochloric acid and then warmed with benedicts solution. This is because the sucrose has been hydrolysed by the acid to glucose and fructose- which are reducing sugars
What is the iodine test for?
Starch
How do you carry the iodine test out?
Add a few drops of iodine, dissolved in potassium iodide solution= mixed with a sample. If solution changes the colour from yellow to purple, starch is present.
What colour does the solution change in the iodine test if theres starch
From yellow to purple
What are reagent strips used for?
testing for the presence of reducing sugars
Benefits of using reagent strips?
Also see concentration of sample from the colour coded chart
What is a colorimeter?
piece of equipment that quantitatively measures the absorbance of light by a coloured solution. The more concentrated the solution the less light will be transmitted
How is a colorimeter experiment carried out?
- Filter placed in colorimeter
- calibrated with water
- Benedicts test carried out
- resulting solutions filtered to remove precipitate
- % of each solution of glucose measured using the colorimeter
- Calibration curve plotted
What are biosensors?
use biological components to determine the presence and concentration of molecules like glucose
What is a lipid?
Molecules containing C,H,O
Fats and oils
Describe a lipids polarity?
Non-polar molecules as the electrons on the outer shell that form the bonds are more evenly distributed than in polar molecules
Meaning there are no positive or negative areas
By lipids being non polar, what does this affect?
Insoluble in water
What are lipids also known as?
Macromolecules
How is a triglyceride made?
Combining a glycerol molecule with three fatty acids
What is a glycerol?
member of the group- alcohols
What group do fatty acids belong to?
Carboxylic acids, consisting of a carboxyl group and a hydrocarbon chain
Explain the reaction within a triglyceride
The hydroxyl group react,forming three water molecules and bonds between the fatty acids and the glycerol molecule. known as ester bonds-esterification
What bonds form between a glycerol and three fatty acids?
Ester bonds as esterification occurs
What is needed to break down a triglyceride?
Three water molecules so hydrolysis reaction can take place
What is a saturated fat
no double bonds present between carbon atoms
Example of a saturated fat?
Fatty acid chains
What is a unsaturated fat?
One or more double bond between carbon atoms
What is a mono-unsaturated
Only one double bond present
What is a polyunsaturated
More than one double bond present
What happens to the molecule if it is unsaturated?
Kinks/bends therefore cant be compact
making it liquid
What type of triglyceride do plants contain?
Unsaturated
Benefits of unsaturated triglycerides
More healthy as normally in oils
What are the disadvantages to saturated fats
lead to coronary heart disease
obesity
What are phosopholipids?
Modified triglycerides
What elements do phospholipids contain?
inorganic Phosphorus, C,H,O
Where is the inorganic phosphate found in the phospholipid
cytoplasm
Why are phospholipids soluble in water
As the phosphate ions have extra electrons therefore negatively charged = making it soluble
2/3 fatty acid chains only appear in the phospholipid, what replaces one of the chains
Phosphate group
Describe the structure of the phospholipid
Hydrophilic head
Hydrophobic tail
How does a phospholipid react with water?
Form on rhe surface with the phosphate head in the water and the hydrophobic tail sticking out of the water- from this called surfactants
Also form a phospholipid bilayer-hydrophobic tail points in , protected from the water by the outer hydrophilic head.
what is a sterol
A type of lipid
What is the structure of a sterol?
Complex alcohol molecule
4 carbon rings structure with a hydroxyl group at one end.
dual hydro-philic/phobic characteristics
Describe the polarity of a sterol
Hydroxyl group is polar, therefore hydrophilic
rest of the molecule hydrophobic
Example of a sterol/
Cholesterol
Where does the body manufacture cholesterol
Liver and intestines
What is the role of cholesterol
Formation of cell membrane
becoming positioned between phospholipids with the hydroxyl group at the periphery of the membrane -adding stability to membrane and regulates the fluid by keep temperatures low
What is manufactured by cholesterol
Vitamin D
Bile
Steroid hormones
As lipids are non-polar, what are their biological roles?
Membrane formation
hormone formation
Electrical insulation
Waterproofing-e.g. birds feathers
Lipids- triglycerides are good at what?
storing energy
In terms of energy, where are lipids stored
Under the skin
What are the advantages of lipids like triglycerides, being stored under the skin
thermal insulation
cushioning to protect vital organs
Buoyancy
What test is use to identify lipids?
Emulsion test
How is the emulsion test for lipids carried out?
Sample mixed with ethanol
mixed with water then shaken
If white emulsion forms on top= lipid present
if stays clear no lipid
