Biological Molecules

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What are electrolytes?
Ions in solution
1 of 50
Give two examples of pentose sugars
Ribose and deoxyribose
2 of 50
Which dissacharide is made up of two glucose molecules bonded together?
Maltose
3 of 50
Which two monosaccharides is lactose made up of?
Glucose and Galactose
4 of 50
How would you test for a non-reducing sugar
Add hydrochloric acid, heat, add NHCO3 to neutralise, test with Benedict's solution should then give a positive result
5 of 50
What is a heteropolysaccharide? Give an example.
A polysaccharide made up of more than one type of monomer e.g. hyaluronic acid- has a role in the immune system
6 of 50
In solution which monosaccharides exist as straight chains and which form cyclic rings?
Triose and tetrose sugars exist as straight chains and pentose and hexose sugars exist as cyclic rings.
7 of 50
Describe the process of esterification (ester bond formation)
The carboxyl group (-COOH) on a fatty acid chain binds to an hydroxyl group (-OH) on glycerol to form a covalent (ester bond)
8 of 50
Name 8 uses of lipids (you cannot have energy source or store)
Phospholipids and cholesterol in membranes, Thermal Insulation, organ protection, steroid hormones, buoyancy, waterproofing, source of water (from respiration)
9 of 50
What are lipids examples of?
Macromolecules- they are not polymers because they are made up of more than one type of monomer
10 of 50
What is the main difference between membrane lipids and triglycerides.
Membrane lipids tend to be amphipathic (polar) whereas those involved in storage do not
11 of 50
what happens when phospholipids are submerged in water?
They form micelles or bilayers
12 of 50
Which is the simplest amino acid and what does its R group consist of?
Glyceine- its R group consists of a single Hydrogen atom
13 of 50
Amino amino acids are amphoteric. What does this mean?
They have both acidic and basic properties and this allows them to act as buffers
14 of 50
How do plants produce amino acids?
By using nitrates in the soil
15 of 50
What happens to excess amino acids?
They cannot be stored because the amino group makes them toxic. They undergo deamination (the process of removing the amino group) in the liver. This is then converted into urea which is then removed as urine.
16 of 50
What do disulfide bridges form between?
R-groups of amino acids which contain sulfur (e.g. cysteine)
17 of 50
Give two examples of simple globular proteins.
Insulin and pepsin
18 of 50
Give two examples of conjugated globular proteins.
Haemoglobin and catalase
19 of 50
What is a conjugated protein?
A globular protein which contains a non-protein component (e.g. a lipid carbohydrate, metal ion or molecule derived from vitamins) called a prosthetic group.
20 of 50
What is the structure and the role of catalase?
It is a quaternary protein made up of 4 haem prosthetic groups. It speeds up the breakdown of hydrogen peroxide- a toxic bi-product of metabolism
21 of 50
Describe the structure of pepsin.
Made up of a single polypeptide chain of 327 amino acids and folds into a symmetrical tertiary structure.
22 of 50
Why is pepsin very stable in acidic conditions?
It only has 4 amino acids with basic R groups but has 43 amino acids with acidic R groups meaning there are few basic groups to accept H+ions- little effect on enzyme's structure in acidic conditions.
23 of 50
What are bones made of?
Collagen- reinforced with calcium phosphate to make them hard
24 of 50
Why are fibrous proteins usually insoluble in water?
They have a high proportion of amino acids with hydrophobic R groups in their primary structure.
25 of 50
What are all the different forms of collagen made up of?
Three polypeptides wound together in a long and strong rope-like structure.
26 of 50
Why is keratin so strong and inflexible?
It is rich in cysteine so has a large number of disulfide bridges between the polypeptides. This is in addition to hydrogen bonds.
27 of 50
List 4 functions of elastin in body tissues.
Allows skin to stretch around our bones and muscles and go back to normal after being pinched. Allows lungs to inflate and deflate. Allows bladder to stretch to hold urine. Helps blood vessels to stretch and recoil maintaining blood pressure.
28 of 50
What is comparative protein modelling?
Protein threading which scans the amino acid sequence against a database of solved structures and produces a set of possible models which would match that sequence.
29 of 50
How many amino acids are there? How many are esstential amino acids?
There are 20 amino acids. Eight are essential in adults and an additional two are essential in growing children (conditionally essential)
30 of 50
What is the cholesterol derivative found in plants and how does it differ from animal cholesterol.
Stigmasterol- It has a double bond between carbon 22 and carbon 23
31 of 50
Why is water an effective transport medium?
It is an excellent solvent- as it is able to separate both negative and positively charged molecules e.g. mineral ions. Its cohesive and adhesive forces allow it to be pulled up a column e.g. the xylem against the force of gravity.
32 of 50
Name the type of reaction that occurs when water is added to break a bond in a molecule
Hydrolysis
33 of 50
Describe the structure of collagen.
3 polypeptide chains twisted around each other/peptide bonds between amino acids/every third amino acid is the same/ left-handed helix/ glycine allows closeness/ H bonds between chains/ no hydrophilic R groups on outside/cross-links/fibril
34 of 50
Why are amino acids described as amphoteric? What property does this give amino acids?
Because they have both acidic and basic properties. The Carboxyl group acts as an acid and the amino group acts as a base. It allows them to act as buffers
35 of 50
Describe 3 ways that haemoglobin is different to collagen.
Haemoglobin is made up of 4 polypeptide chains rather than 3. It is a globular protein rather than a fibrous one and it is soluble
36 of 50
How does insulin carry out its function?
Binds to glycoprotein receptors in muscle/fat cells to increase uptake and consumption of glucose
37 of 50
Describe the structure of pepsin and explain how it is related to its function (digesting protein in the stomach)
It is made of a single polypeptide chain of 327 amino acids, folded into a symmetrical structure. It is held together by H bonds + disulfide links. It has 43 amino acids with acidic R groups, so remains stable in the acidic conditions of the stomach
38 of 50
What is tropoelastin and what does it form? Why is the material it forms so strong?
A molecule that can stretch and recoil/Contain alternating hydrophobic and lysine-rich areas/Elastin formed when multiple tropoelastin molecules aggregate via interactions between hydrophobic areas/Structure stabilised by cross-links involving lysine
39 of 50
Why is keratin so strong?
It is rich in cysteine, a sulfur containing amino acid, so has a large number of disulfide bridges between the polypeptide chains. Along with hydrogen bonding this makes the molecule strong, inflexible and insoluble.
40 of 50
Why is there an unpleasant smell when hair or skin is burnt?
Because they are made predominantly of keratin- which contains large quantities of sulfur
41 of 50
List four places in the body which contain/are made of collagen.
In artery walls/ tendons which connect muscles to bones, allowing them to pull on bones/ Bones are made from collagen and reinforced with calcium phosphate to make them hard/ Cartilage and connective tissue
42 of 50
Describe the structure of insulin
Made of two polypeptide chains/A chain begins with a section of alpha-helix and the B chain ends with a section of beta-pleat/Both chains folded into a tertiary structure and then joined together by disulfide links.
43 of 50
What do ionic bonds in the tertiary structure of proteins form between?
Between carboxyl and amino groups which are part of the R group.
44 of 50
How can protein denaturation occur?
H bonds can be broken by high temps or pH changes/ Disulfide bonds can be broken by reducing agents/ ionic bonds can be broken by pH changes
45 of 50
What is Ab initio protein modelling and what is a disadvantage of it?
When a molecule is built based on the physcial and electrical properties of the atoms in each amino acid. It can produce multiple solutions for the same sequence so sometimes other methods need applying to reduce the number of solutions.
46 of 50
What is comparative protein modelling?
Protein threading which scans the amino acid sequence against a database of solved structures and produces a set of possible models which would match that sequence.
47 of 50
Why is protein modelling useful?
Predicting the same of a molecule from its primary structure allows you to predict the occurence of biologically active binding sites which can help in identifying new medicines.
48 of 50
What is tropocollagen?
The long fibrils which cross-links to form bundles of collagen fibres
49 of 50
What disaccharide is made up of two beta glucose molecules bonded together by glycosidic bonds?
cellobiose
50 of 50

Other cards in this set

Card 2

Front

Give two examples of pentose sugars

Back

Ribose and deoxyribose

Card 3

Front

Which dissacharide is made up of two glucose molecules bonded together?

Back

Preview of the front of card 3

Card 4

Front

Which two monosaccharides is lactose made up of?

Back

Preview of the front of card 4

Card 5

Front

How would you test for a non-reducing sugar

Back

Preview of the front of card 5
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