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A LEVEL BIOLOGY > Chapter 3 > Flashcards

Chapter 3 Flashcards

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1
Q

Why is water a polar molecule?

A

What is a polar molecule because the hydrogen in the oxygen water are covalently bonded however the shared Hydrogen electrons are pulled towards the oxygen electrons giving it a partial negative charge

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2
Q

How do hydrogen bonds form between water molecules?

A

waters polarity allows it to form hydrogen bonds because the slightly positive hydrogen atoms will attract the slight negative oxygen atoms of the other molecules

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3
Q

Why does water have a high specific heat capacity? How does this relate to living organisms

A

Water has a high specific heat capacity because it takes a lot of energy to raise the temperature of water because the hydrogen bonds can absorb a lot of energy therefore it makes a good habitat as it doesn’t experience rapid temperature changes for organisms that cannot survive is varied conditions

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4
Q

Why does water have a high latent heat of evaporation and how does this relate organisms?

A

Water has a high latent heat of evaporation because the strong hydrogen bonds take a lot of energy to break so its useful because when you sweat a lot energy is lost when it evaporates cooling the organism

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5
Q

Why is water cohesive and adhesive and how does this relate to living organisms?

A

Polarity of water molecules make a very cohesive as a hydrogen bonds mean they are attracted to each other water is also adhesive which allows water to rise up a narrow tube against the force of gravity in transpiration

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6
Q

Why is water less dense when solid and how does this relate to living organisms?

A

When water freezes the hydrogen bonds form a lattice holding the molecules further apart than in the liquid making it less dense. This is useful because when water freezes ice floats and forms an insulating layer on the surface of water living organisms don’t freeze

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7
Q

Why is water a good solvent?

A

Water is polar so it can dissolve polar solutes as the Delta plus hydrogen atoms are attracted to the negative ions and the Delta negative oxygen atoms attract the positive ions pulling them away from the lattice this is useful as polar solutes can be dissolved in the water in the blood and be transported

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8
Q

What are monosaccharides?

A

A monosaccharide is a single sugar molecule

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9
Q

What is a carbohydrate?

A

A carbohydrate is a saccharide made up of hydrogen, carbon and oxygen

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10
Q

What is the general formula for carbohydrates?

A

Cx(H2O)y

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11
Q

What type of monosaccharide is glucose?

A

Glucose is a hexose monosaccharide because it has six carbons

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12
Q

What are the two types of glucose? Draw a diagram of both outlining the differences

A

Alpha and beta glucose check diagrams in textbooks

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13
Q

How does the structure of glucose relate to its function?

A

Due to the water molecules in its structure glucose is a polar molecule so it’s soluble in water which allows it to be transported more easily

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14
Q

What type of molecule is ribose?

A

Ribose is a pentose monosaccharide because it has five carbons

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15
Q

Draw a diagram of ribose

A

Check in textbook

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16
Q

What is a disaccharide?

A

A disaccharide is a molecule containing two monosaccharides joined together by a glycosidic bond

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17
Q

How are disaccharide formed and broken down?

A

Disaccharides are formed through synthesis of two monosaccharides which is a condensation reaction and broken down by hydrolysis when a molecule of water reacts with the Glycosidic bond

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18
Q

What Is a polysaccharide?

A

Polysaccharide is a polymer made of many monosaccharides

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19
Q

What is starch?

A

Starch is the main storage molecule in plants it’s a mixture of two polysaccharides amylose and Amylopectin.Amylose is a long unbranched coiled compact chain of alpha glucose and Amylopectin is a Long, branch chain of alpha glucose that helps enzymes break down the molecule quicker some more energy can be released

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20
Q

Why is starch insoluble?

A

Is insoluble so it doesn’t cause water to enter cells by osmosis

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21
Q

What is glycogen?

A

Glycogen is the animal storage molecule is an extremely branched chain of alpha glucose so the energy can be released quickly which is important for animals who are more active

22
Q

What is Celulose?

A

Cellulose is a long unbranched chain of beta glucose alternate molecule are turned upside down so they can bond and the chains are linked together by hydrogen bonds to form microfibres which are hard to break down so form fibre in our diet

23
Q

What are lipids

A

Lipids are large complex molecules known as macromolecules which are nonpolar and insoluble

24
Q

What are triglycerides

A

Triglycerides are lipids with one molecule of glycerol and 3 fatty acids attached making a hydrophobic tail

25
Q

How are triglycerides formed

A

triglycerides are formed in esterification where the hydroxyl groups of the glycerol head and three fatty acid tails interact in a condensation reaction forming ester bonds and releasing three water molecules

26
Q

Why are triglycerides good energy storage molecule

A

The long hydrocarbon tail contains a lot of chemical energy which is released when they’re broken down
They bundles together as insoluble droplets they don’t cause water to move into cells by osmosis

27
Q

What is a phospholipid

A

Phospholipids a modified triglycerides which contain a phosphate group which replaces a fatty acid

28
Q

What is the function of phospholipids and why are they effective

A

Phospholipids are effective as part of cell membranes because
They have a polar end due to the fatty acid tails and a nonpolar and due to the phosphate group which allows them to form a bilayer arrangement with a hydrophobic centre acting as a barrier to water soluble substances

29
Q

What is cholesterol

A

Cholesterol is a type of lipid known as a sterol with a hydrocarbon ring structure attached to a hydrocarbon tail

30
Q

What is the function of cholesterol and why is it effective

A

Cholesterol strength and cell membranes because
cholesterol has a small size and flattened shape so they are able to fit in between phospholipids
cholesterol binds to hydrophobic tails of phospholipids packing the more closely together so it is less fluid and more rigid

31
Q

What is the difference between a saturated and unsaturated lipid

A

Saturated lipid has no double carbon bond so it is saturated with hydrogen EG fats
Unsaturated lipids have at least one double carbon bond EG oil

32
Q

What is a protein

A

A polymer made up of amino acids

33
Q

What are amino acids draw a diagram

A

Amino acids have a general structure a variable group carboxyl group and amino acid group attached to a carbon and a hydrogen

34
Q

How are peptides synthesized

A

when a hydroxide in the carboxyl group and the hydrogen from the amine group react producing water this forms a peptide bond and when many amino acids are joined a polypeptide is formed

35
Q

Explain the levels of protein structure

A

Primary structure is the sequence of amino acids in the polypeptide chain
secondary structure is the hydrogen bonds that form making it coil into an alpha helix or beta pleated sheet
tertiary structure is when the protein folds into its final shape due to ionic bonds disulfide bonds hydrophobic and hydrophilic interactions and hydrogen bonds
Quaternary structure is where two or more proteins interact and assembled together

36
Q

What is a globular protein

A

A globular protein is a spherical water soluble protein but the hydrophilic r group push to the outside

37
Q

Give an example of a globular protein

A

Insulin is a globular protein used in the regulation of blood glucose concentration and made up of two polypeptide chains

38
Q

What is a conjugated protein

A

conjugated protein is a globular protein with a prosthetic group

39
Q

Give two examples of conjugated proteins

A

haemoglobin the red oxygen-carrying pigment of red blood cells is a quaternary protein made up of two alpha and 2 beta subunits which each contain a prosthetic heme group with an iron ion which combine with oxygen allowing transport

amylase is an enzyme that catalyses the breakdown of starch in the digestive system and it’s a single chain of amino acid

40
Q

What are fibrous proteins

A

Fibrous proteins are long insoluble structural proteins

41
Q

Give three examples of fibrous proteins

A

keratin is a fibrous protein found in hair skin and nails and can be flexible or soft depending on the degree of the disulfide bonds
elastin is a fibrous protein found in elastic fibres such as the walls of blood vessel or alveoli and it is a quarter protein made from tropoelastin molecules
collagen is a fibrous protein and it is a connective tissue found in the nervous system made up of 3 polypeptides round in a long strong rope like structure

42
Q

How can you test for reducing sugars and what is a reducing sugar

A

Reducing sugars are all monosaccharides and some disaccharides including glucose maltose and lactose
Add Benedict’s reagent to the sample heat in a water bath and a positive result will produce a coloured precipitate which changes depending on the concentration from blue to green to yellow to orange to brick red

43
Q

How can you test for reducing sugars and what is a reducing sugar

A

Reducing sugars are all monosaccharides and some disaccharides including glucose maltose and lactose
I Benedict’s reagent to the sample heat in a water bath and a positive turtle produce a colour precipitate which changes depending on the concentration from blue to green to yellow to orange to brick red

44
Q

How can you test for a non reducing sugar and what is a non reducing sugar

A

A non reducing sugar EG sucrose
add dilute hydrochloric acid heat in a water bath neutralized with sodium hydrogen carbonate is a test is positive it will for my colour precipitate when Benedict’s reagent is added from blue to green to yellow to orange to brick red

45
Q

How do you test for starch

A

Add iodine dissolved in potassium iodide solution and it will turn blue black of starch is present

46
Q

How do you test for proteins

A

A few drops of sodium hydroxide solution and copper sulphate solution it will turn purple if a protein is present

47
Q

How do you use test strips for reducing sugars

A

Test strips dipped in a sample change colour if a reducing sugar is present which can be compared to a chart to determine concentration

48
Q

How do you test for lipids

A

Shake the sample with ethanol for a minute pour into water and it will turn milky if a lipid is present

49
Q

How can you get a quantitative estimate of how much glucose is in a solution

A

You can use colorimetry
A 10 cm of 40 m glucose solution to a test tube and 5 cm cubed distilled water to 4 others
Draw 5 cm from the first and add to the second repeat three more times
Do a Benedict’s test on each
Centrifuged to remove precipitate
Use a red filter colorimeter to measure each for absorbance
make a calibration curve and test the unknown solution and use the curve to find its concentration

50
Q

What is a biosensor

A

Biosensor is a biological component such as an enzyme which determines the present and concentration of a molecule

51
Q

How can you use chromatography to identify unknown amino acids

A

Draw a pencil line at the bottom of the chromatography paper
Add a spot of the sample on it
Add a solvent to a beaker and dip the bottom of the paper in it cover with a lid
Take the paper out when it’s almost reaches the top and Mark the solvent front then leave to dry
To see amino acids as ninhydrin solution
calculate the RFID to identify which is distant travel by sollew over distance travelled by solvent

A LEVEL BIOLOGY (18 decks)

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