Biological Molecules Flashcards

1
Q

What is a biological molecule?

A

An organic molecule produced by cells

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2
Q

What are some examples of biological molecules?

A

Carbohydrates
Lipids
Amino acids
Nucleic acids

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3
Q

What is an organic molecule?

A

Molecules that contain carbon bound to hydrogen

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4
Q

How do many organic molecules exist?

A

As monomers and polymers

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5
Q

Define a polymer

A

Many monomers in a set repeating sub-unit, forming a backbone

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6
Q

How are polymers formed?

A

hen many polymers join via a condensation reaction forming a chemical (covalent) bond, whilst expelling a molecule of water each time

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7
Q

What is a monomer?

A

A small molecule, that when in a repeating sub-unit can form a polymer via condensation reactions

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8
Q

True or False:
All the monomers in a polymer are identical

A

False- allows for different structures and codes, e.g. DNA and Proteins

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9
Q

What is a backbone?

A

The repeating sub-unit that monomers form

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10
Q

What does R stand for?

A

Variable/Radical/Rest of molecule

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11
Q

How are polymers reverted to monomers?

A

Hydrolysis reactions: a molecule of water is inserted into each bond as to break the bond, and revert the polymer into the monomers

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12
Q

What are the two main components of many lipids?

A

Glycerol and fatty acids

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13
Q

What is the formula of glycerol?

A

C3H8O3

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14
Q

What is the formula of fatty acids (saturated)?

A

COOH(CH2)nCH3

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15
Q

How do fatty acids join to glycerol, break from glycerol and how many molecules of water are produced?

A

Condensation reaction
Hydrolysis reaction
3 molecules of water

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16
Q

What does the fatty acid carbon chain start with?

A

A carboxyl (-COOH) group

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17
Q

How do fatty acids have varying properties?

A

By having varying carbon chain lengths from 12-18 carbons to 10-30, and leafing to different structures

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18
Q

What do complex saturated/unsaturated fatty acids have?

A

Sidechains such as whole molecules or oxygen

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19
Q

How do glycerol-based lipids exist and what is their main function?

A

Phospholipids (with phosphate group): Main component of cell-membrane, fluid-mosaic model
Triglycerides: Storage in adipose (body fat) tissue, insulin

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20
Q

Why are phospholipid heads hydrophilic?

A

The phosphate group allows for polarity so the water molecules will interact with the head of the phospholipid

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21
Q

Why are phospholipid tails hydrophobic?

A

There is no polarity for the water molecules to interact with, so the fatty acids will repel the molecules

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22
Q

State what an amphipathic molecule is

A

When the molecule contains both polar and non-polar regions, thus allowing molecules (like H2O) to attach and interact with them

23
Q

What are the health benefits of unsaturated fatty acids being more fluid like?

A

Allows the cell membrane to have more fluidity, fluid mosaic model
Lower chance of causing arterial plaque build up than more solid like fats, as the unsaturated fatty acids are pushed along

24
Q

What is an eicosanoid?

A

A form of fatty acid used as a signaling molecule

25
Q

What is a steroid?

A

A lipid consisting of four fused carbon rings, with a side chain
Mostly associated with hormones like testosterone and oestrogen

26
Q

How are sterols formed?

A

If a steroid has a hydroxyl (-OH) group they become an alcohol and so a sterol e.g. cholesterol

27
Q

What are the functions of sterols and steroids?

A

Sterol: Regulates fluidity
Steroid: Growth hormones

28
Q

What are carbohydrates?

A

Molecules that contain only carbon, hydrogen and oxygen atoms
Also need multiple OH groups and a C=O bond in the linear monomer; aldehydes and ketones

29
Q

What are examples of simple sugars?

A

Monosaccharides: glucose, fructose, galactose
Disaccharides: maltose, sucrose, lactose

30
Q

What are examples of complex sugars?

A

Polysaccharides: starch, cellulose, glycogen

31
Q

How are complex sugars formed?

A

Condensation reactions of many simple sugars

32
Q

What are some uses of carbohydrates?

A

Release energy for respiration
Store glucose as glycogen
Form glycoproteins and glycolipids by combining with proteins and lipids, leading to hormones and cell signaling
Incorporation into and synthesis of other biological molecules

33
Q

What formula do most but not all dietary monosaccharides have?

A

C6H12O6

34
Q

How are the sugars named?

A

Dependent on the number of carbon atoms in the carbon chain, e.g. glucose= C6H12O6 so is a hexose sugar, and can be broken into two triose sugars

35
Q

What do DNA and RNA nucleotides consist of?

A

A phosphate group, a pentose sugar and a nitrogenous base

36
Q

What are the 5 possible nitrogenous bases

A

Adenine
Guanine
Cytosine
Thymine (DNA only)
Uracil (RNA only)

37
Q

What are the two main types of nitrogenous bases?

A

Purine: Two C-N rings
Pyrimidine: One C-N ring

38
Q

Which bases are purines and which bases are pyrimidines?

A

Adenine and Guanine= purines (Adenosine and Guanosine nucleotides)
Cytosine, Thymine and Uracil= Pyrimidines (Cytidine, Thymidine and Uridine nucleotides)

39
Q

What is are examples of polymers of nucleotides (polynucleotides)?

A

Chromosomes/Chromatin
mRNA strands
miRNA strands

40
Q

How can the strands form hydrogen bonds and why?

A

The strands can link intermolecularly to form double stranded molecules- but need to be between complementary base pairs as to be physically possible
A and T/U
C and G

41
Q

What are amino acids and how many of them are there in standard human proteins?

A

Monomers of polypeptides
20 variants

42
Q

What is the structure of an amino acid?

A

A central carbon atom with a carboxyl terminal on the left, and an amine terminal on the right, with a hydrogen atom below it and an R chain

43
Q

What are proteins?

A

A functional group comprised of polypeptides

44
Q

Where do polypeptides start and end?

A

They start at the “N” terminus and end at the “C” terminus

45
Q

How can you describe the structure of a polypeptide?

A

Repeating N-C-C backbone with R groups and oxygen and hydrogen atoms attached to it

46
Q

How can proteins be materials/nutrients?

A

When they are referred to by the individual chemical materials they are predominantly formed from, amino acids and/or polypeptide chains

47
Q

How can proteins be individual structures?

A

When referred to as the functional unit predominately made of that material, e.g., polypeptides

48
Q

What is the primary structure of a protein?

A

The sequence of amino acids, held together by covalent (peptide) bonds, only altered by chemical reactions

49
Q

What is the secondary structure of a protein?

A

How the polypeptide folds locally; folding in a specific part of the chain- as they will fold into or onto each other
Can fold into alpha helices or beta pleated sheets
Held together by hydrogen bonding

50
Q

What is the tertiary structure of a protein?

A

The 3D shape of the polypeptide, how the entire polypeptide folds up
Held together by: Hydrogen bonds, electrostatic forces, hydrophilic/hydrophobic interactions, and covalent bonds (disulphide bridges) as of the R groups
Only partially broken by heat as disulphide bridges>H bonds, so stronger than secondary structure

51
Q

What is the quaternary structure of the protein?

A

The number of polypeptide chains or the number of prosthetic groups

52
Q

What is a prosthetic group?

A

The non-amino acid component

53
Q

Why do proteins denature and what are the consequences of this?

A

Proteins are mostly held in a shape by intermolecular forces
Attractions and repulsions within the molecule and with the surroundings

Heat and pH can break these bonds, causing the folded structure of the protein to unravel (denature)

The shape of a protein is often directly related to its function. It can not work when denatured.