Module 2- Bio Molecules Flashcards

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1
Q

What elements are found in carbohydrates?

A

Carbon, Hydrogen and Oxygen

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2
Q

What are monosaccharides and give some examples?

A

Simple sugars containing 3-7 carbon atoms
glucose, galactose and fructose

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3
Q

Describe glucose and its function

A

hexose sugar (has 6 carbons in its structure)
chemical formula=C6H6O12
important source of energy in humans
during cellular respiration the energy released from glucose helps to make adenosine triphosphate (ATP)

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4
Q

What are isomers?

A

Isomers have the same molecular formula but a different arrangement of atoms. e.g alpha and beta glucose

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5
Q

Describe how disacchardies and polysaccharides form

A

Di-when 2 monosaccharides join via a condensation reaction
Poly-when more than 2 polysaccharides join together

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6
Q

State all 3 condensation reactions between monosaccharides

A

Glucose+Glucose->maltose
Glucose+Fructose->sucrose
Glucose+Galactose->lactose

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7
Q

What is sucrose known as?

A

A common table sugar

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8
Q

What is lactose known as?

A

The sugar found in milk

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9
Q

What are polysaccharides joined together by?

A

Glycosidic bonds

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10
Q

Examples of polysaccharides

A

starch, glycogen, chitin, cellulose

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11
Q

Structure and function of starch

A

-Polysaccharide formed by the condensation reaction between alpha glucose molecules
-Main energy storage material in plants
-Stored in the seeds of plants
-Is broken down into glucose by plants when they need more energy
-Acts as a source of food for animals
-Doesn’t change the water potential in a cell as it’s insoluble in water

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12
Q

Structure and function of amylose?

A

-Linear chain of alpha glucose monomers
-Helical structure
-Means their structure is compact and well suited for being a chemical energy store in plants
-1,4 glycosidic bonding
-Stabilised by hydrogen bonding between adjacent hydroxyl groups

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13
Q

Structure and function of amylopectin?

A

-alpha glucose that has 1,4 and 1,6 glycosidic bonding
-branched structure allows more glucose to be stored in the chemical energy store of the plant
-enzymes to easily access the glycosidic bonds for hydrolysis when glucose is required.

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14
Q

What is the structure and function of glycogen?

A

-energy reserve in animals
-alpha glucose
-1,4 and 1,6 glycosidic bonds
-highly branched structure allows good storage molecule as it is so compact as well as glucose being released quickly when needed
-when blood glucose levels decrease glycogen is broken down to release glucose. This is known as glycogenolysis

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15
Q

What is the structure and function of cellulose?

A

-long chain of beta glucose due to 1,4 beta glycosidic bonding
-cell walls are mostly made up of cellulose due to the strength of microfibril fibres adding rigidity and structure to the cell walls.
-cant be digested by human digestive enzymes

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16
Q

What is the important of water?

A

-major component of cells
-used as a reactant in cells
-provides structural support in cells
-keeps organisms at optimum body temp

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17
Q

Water is a polar molecule …

A

-oxygen atoms in water are slightly negatively charged (electronegative)
-hydrogen atoms in water are slightly positively charged (electropositive)
-hydrogen bonding due to uneven charge distribution

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18
Q

Universal solvent…

A

-ions and polar molecules can easily dissolve in water
-negative ends of water molecules are attracted to positively charged ions
-allows chemical reactions in organisms to happen much more quickly

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19
Q

Cohesion/adhesion…

A

-strong attraction between water molecules due to hydrogen bonding is cohesion
-polar bonds also gives water an adhesive property as it is able to cling to other polar surfaces
-Water allows for efficient transport of nutrients and waste

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20
Q

High surface tension…

A

-water molecules at the surface are more strongly attracted to each other than the air surrounding
-water striding insects are able to walk on the surfaces of water

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21
Q

High heat capacity…

A

-hc is the amount of heat 1kg of a substance must absorb to change its temp by 1degC
-hydrogen bonds let water molecules absorb a large amount of heat without changing its chemical state
-allows warm blooded animals to more evenly disperse the heat in their bodies and maintain homeostasis
-helps stabilise large bodies of water and prevents aquatic animals suffering great fluctuations in temp

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22
Q

Changes in density…

A

-the configuration of hydrogen bonds in water cause it to expand when frozen
-this causes ice to have a lower density than water
-bodies of water always freeze from the top down as the ice on the surface acts as an insulator to protect water below from freezing and allowing organisms to survive.

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23
Q

What are the monomers and polymers of proteins?

A

monomers- amino acids
polymers- polypeptides

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24
Q

What does the structure of an amino acid look like?

A

-4 atoms bonded to the central carbon
-NH2 (amine group)
-COOH (carboxylic acid group)
-H
-R (side group)

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25
Q

How many amino acids are there that are common in all organisms? How many of these are essential for humans and why?

A

20
9 because the human body can’t produce them so have to be obtained from the diet

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26
Q

What are the end amino acids in the polypeptide chains called?

A

N terminal and C terminal

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27
Q

Where is the peptide bond formed?

A

between the carboxyl group on one amino acid and the amino group of another amino acid

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28
Q

What is the primary structure and what is it determined by?

A

sequence of amino acids in a polypeptide chain and is determined by the gene encoding protein

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29
Q

What is the secondary structure?

A

-amino acids in a polypeptide chain can form hydrogen bonds between other amino acids within the chain
-this causes alpha helix or beta pleated sheet structures

30
Q

How stable is the secondary structure?

A

the structure is stable although the hydrogen bonds are quite weak
-stability is decreased by environmental factors that weaken the hydrogen bonds e.g temp and ph

31
Q

What is the tertiary structure?

A

-the secondary polypepyide folds further to form a tertiary 3D polypeptide chain
-involves bonds forming between R groups
-can be coiled or folded
-involves ionic, hydrophilic/hydrophobic, disulfide and hydrogen bonding

32
Q

What happens if the 3D shape in the tertiary structure is lost?

A

it may no longer be functional

33
Q

What are ionic bonds?

A

-have a positive or negative charged ion in their R group
-quite rare
-strong bonds

34
Q

What are disulfide bonds?

A

covalent bonds within proteins containing cysteine amino acids

35
Q

What are hydrogen bonds?

A

Relatively weak but when there are many stability increases

36
Q

What are hydrophilic bonds?

A

attracted to water so orientate themselves towards the outside of the 3D shape

37
Q

What are hydrophobic bonds?

A

repelled by water so cluster together on the inside of the protein

38
Q

What is the quaternary structure?

A

More than 1 polypeptide chain
Bonds that hold the structure together are the same that are found in the tertiary structure
e.g collagen, insulin

39
Q

What are conjugated proteins?

A

have one or more non protein groups attached (prosthetic groups)to help them carry out their function
e.g glycoproteins

40
Q

What is the structures and function of globular proteins?

A

-rough spherical shape
-tertiary structure is what leads to the round structure
-soluble in water due to many hydrophilic R-groups on the outside of the polypeptide chain
-have relatively unstable structures as bonds are often susceptible to the effects of a change in the environment
-functions include- regulation of bio processes by transmitting messages, enzymes active site, transport

41
Q

Name 3 examples of globular proteins

A

haemoglobin, insulin, salivary amylase

42
Q

What is the structure and function of haemoglobin?

A

-conjugated protein
-carries oxygen around in the blood of humans
-prosthetic group is the haem group
-4 polypeptide chains (2 alpha and 2 beta) which all have a haem group that contains iron that the oxygen binds to

43
Q

What is the structure and function of insulin?

A

-made from 2 polypeptide chains joined together
-hormone secreted by the pancreas
-helps to regulate blood glucose levels
-its solubility allows it to be transported in the blood to the tissues where it acts
-polypeptide chains are held together by disulfide bonds

44
Q

What is the structure and function of salivary amylase

A

-made from 1 polypeptide chain that is twisted and folded
-catalyses the breakdown of starch in the digestive system
-primary structure consists of 496 amino acids
-secondary structure contains sections of alpha helix and beta pleated sheet
-tertiary structure has disulfide, hydrogen and ionic bonds

45
Q

What is the structure and function of fibrous proteins?

A

-structural proteins that are used to build, strengthen and protect cells and tissues
-strong long molecules with a high proportion of hydrophobic R-groups in their primary structure
-the repetitive amino acid sequence leads to very regular, linear sequences
-are insoluble in water

46
Q

What are 3 examples of fibrous proteins?

A

collagen,keratin,elastin

47
Q

Structure and function of collagen

A

-found in ligaments, tendons, muscles, cartilage, bone and skin
-made up of 3 polypeptides wound together in a long rope like structure
-is strong but flexible

48
Q

Structure and function of elastin

A

-found within elastic fibres e.g. walls of blood vessels and alveolus
-have the ability to stretch and recoil as made up of stretchy protein fibres called tropoelastin

49
Q

Structure and function of keratin

A

-contains lots of cyteine resulting in many disulfide bonds
-form strong, inflexible and insoluble materials
-2 parallel alpha helices twisted around each other
-found in hair and nails

50
Q

What are cations?

A

-positive
-don’t contain carbon
-ions gained through nutrition
-cytoplasm and other bodily fluids maintain optimum levels of each ion

51
Q

What are 3 examples of cations and what do they do?

A

Ca2+ ions= carry signals around organisms and help maintain potential difference across membranes

K+ ions= found in tissues of animals and plants and are essential for propagation of action potentials within nervous tissue

NH+4 ions= are a metabolite of amino acids used to make some nitrogen based compounds in the body. Excess NH+4 ions are excreted as waste products in urea.

52
Q

What are anions?

A

-negative
-don’t contain carbon

53
Q

What are phosphate ions?

A

PO4 3-
-are an essential part of the sugar phosphate backbone of DNA molecules

54
Q

What are 4 examples of anions and what are their functions?

A

Cl- ions are important electrolytes and are involved in the transmission of impulses along nerve cells

HCO3- are alkaline so help neutralise the stomach acid

OH- ions help maintain a suitable pH level in all organisms

NO3- ions are found in fertilisers

55
Q

What is the test for lipids?

A

Emulsion test
-Place a sample in a test tube with ethanol
-Shake well and leave upright for 2-3 minutes
-Pour solution into a test tube containing distilled water
-If a lipid is present a white milky layer will form

56
Q

What is the test for proteins?

A

Biuret test
-add sample to distilled water and biuret solution
-shake solution and leave upright for 5 mins
-if proteins are present solution will change colour from blue to purple
-the result will only be positive if amino acids are joined together by peptide bonds

57
Q

What is the test for reducing sugars?

A

Benedicts test
-place a sample in a test tube and add 10 drops of Benedicts
-place in a boiling water bath for 3-5 minutes
-if green or yellow there are traces of reducing sugars
-if orange or red there are moderate levels of reducing sugars
-if brick red there are large amounts of reducing sugars

58
Q

What is the test for non reducing sugars?

A

-Show a negative result to the benedicts test
-boil in dilute HCl to hydrolyse non reducing sugars
-neutralise solution by adding sodium bicarbonate
-repeat benedicts test
-if solution remains blue no sugar is present

59
Q

What is the test for starch?

A

Iodine test
-add sample to test tube
-add a few drops of iodine
-if starch is present it will change from orange to blue/black

60
Q

How does colorimetry work?

A

-allows for the colour of a substance to be quantified
-works by shining a light with a known wave length range through a solution and recording what comes out the other side

61
Q

How do biosensors work?

A

-are made up of a biological element and a physiochemical detector
-produce electrical signals from biological responses

62
Q

How does chromatography work?

A

separates substances based on their interactions with the mobile and stationary phases.

63
Q

What is the mobile phase in chromatography?

A

solvent

64
Q

What is the stationary phase in chromatography?

A

solid support

65
Q

How does chromatography separate substances?

A

uses different elution times of substances to separate substances and calculate rf values to identify substances

66
Q

What is used in gas chromatography?

A

retention time

67
Q

Describe how to carry out TLC chromatography?

A

-use an aluminium tlc plate coated in alumina
-place in a beaker of solvent e.g water
-more polar substances interact more with the stationary phase
-rf values are subject to conditions

68
Q

What chemical elements do lipids contain?

A

carbon, hydrogen and oxygen (sometimes phosphorus)

69
Q

What is the structure and function of triglyceride?

A

-made up of 1 glycerol molecule and 3 fatty acid tails which can be saturated or unsaturated
-insoluble in water as hydrophobic
-provides cushioning to protect vital organs and thermal insulation

70
Q

What is esterfication?

A

-is an exmaple of a condensation reaction where hydroxyl groups of the glycerol molecule react with the hydroxyl groups on the fatty acid tails to form an ester bond

71
Q

Describe the structure and function of a phospholipid

A

-contain phosphorus as well as C,H,O
-glycerol back bone with 2 fatty acid tails and 1 phosphate hydrophilic head
-1 tail is saturated and the other is unsaturated but they are both hydrophobic
-provide buoyancy for aquatic organisms
-make up cell membranes

72
Q

Describe the structure and function of cholesterol

A

-is a sterol
-has hydrophilic and hydrophobic characteristics
-forms cell membranes adding stability and regulating fluidity