Biological Molecules Flashcards

(56 cards)

0
Q

What are the functions of proteins

A

Structure transport enzymes antibodies most hormones

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1
Q

What are the functions of carbohydrates.

A

Energy storage and supply. Structure in some organisms

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2
Q

What are the functions of lipids

A

Membranes energy supply thermal insulation protective layers electrical insulation in neurones some hormones

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3
Q

What are the functions of vitamins and minerals

A

Form parts of some large molecules and take part in some metabolic rectioms. Some act as coenzymes or enzyme activators

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4
Q

What are the functions of nucleic acids

A

Information molecules carry instructions for life

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5
Q

What are the functions of water

A

Takes part in many reactions, support in plants, solvent for most metabolic reactions, transport

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6
Q

Define metabolism

A

The sum total of all biochemical reactions taking place in the cells of a organism

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7
Q

Describe covalent bonds

A

Former when electrons are shared between atoms. Very strong. Covalently bonded atoms form new molecules.

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8
Q

Describe hydrogen bonding

A

Form when a slightly negatively charged part of a molecule comes close to a slightly positively charged hydrogen atom. Not strong bonds.

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9
Q

Describe ionic bonds

A

Attraction between oppositely charged ions

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10
Q

Describe a condensation reaction

A

Catalysed by enzymes. Water molecule released, new covalent bond formed. Larger molecule formed by bonding together of smaller molecules.

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11
Q

Describe a hydrolysis reaction

A

Catalysed by enzymes. Water molecule used. Covalent bond broken, smaller molecule formed by splitting of a larger molecule.

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12
Q

What are the 6 properties of water

A

Solvent liquid cohesion freezing thermal stability metabolic reactant

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13
Q

Describe how waters property of being a solvent relates to its function with an example

A

Metabolic processes in all organisms rely on chemicals being able to react together in solution. Dissolved chemicals take part in processes such as respiration and photosynthesis

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14
Q

Describe how waters property of being a liquid relates to its function with an example

A

Movement of materials within organisms requires a liquid transport medium eg blood in animals or vascular tissues in plants

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15
Q

Describe how waters property of cohesion relates to its function with an example

A

Water molecules stick to each other creating surface tension. Also makes long thin water columns very strong and hard to break. Eg transport in xylem in transpiration stream. Animals like pond skaters can use tension to walk on water surface

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16
Q

Describe how waters property of freezing relates to its function with an example

A

Water freezes forming ice on the surface which insulates water below so this is less likely to freeze. Habitat eg polar bears live on Ice sheets. Lakes tend not to freeze fully so aquatic organisms can survive in lake if top frozen

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17
Q

Describe how waters property of thermal stability relates to its function with an example

A

Large bodies of water have fairly constant temperatures and evaporation of water can cool surfaces by removing heat. Oceans have stable terms true as habitat. Can use evaporation to cool eg sweating

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18
Q

Describe how waters property of being a metabolic reactant relates to its function with an example

A

Water can be a reactant in some chemical processes eg hydrolysis reactions and photosynthesis

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19
Q

Describe monosaccharides

A

Monomers of carbohydrates. Soluble in water sweet tasting and form crystals. Grouped according to number of carbons, 3 is triose, 5 is pentose and 6 is hexose which is the most common

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20
Q

Describe a disaccharide

A

Formed when 2 monosaccharides join

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21
Q

Describe a polysaccharide

A

Formed when more than 2 monosaccharides join together

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22
Q

Describe alpha glucose

A

Where hydroxyl group is below the hydrogen molecule

23
Q

Describe beta glucose

A

Where hydroxyl group is above the hydrogen molecule ABBA

24
How are monosaccharides joined together
By a condensation reaction, a new covalent bond called a glycosidic bond is formed and water is released. Reverse of this is hydrolysis. Catalysed by enzymes
25
Describe starch
Main energy storage molecule in plants. Amylose is long straight chains and amylopectin is branched. Starch is stored in chloroplasts and elsewhere in cells in membrane bound starch grains. Can be broken down into glucose which can be respired to release energy
26
Describe how the structure of starch relates to its function
It is insoluble in water so it doesn't cause water to enter cells by osmosis which would make cells swell so it is good for storage
27
Describe glycogen
Main energy storage material in animals. Animal cells store excess glucose as glycogen which is another polysaccharide of alpha glucose and is highly branched
28
Describe how the structure of glycogen relates to its function
Lots of branches so stored glucose can be released easily and quickly. Compact so good for storage
29
Describe cellulose
Major component of cell walls in plants. Made of long unbranched chains of beta glucose. Chain is straight as bonds between sugars are straight. Cellulose chains linked together by hydrogen bonds to form strong fibres called microfibrils
30
Describe how the structure of cellulose relates to its function
Strong fibres mean cellulose provides structural support eg in cell walls. Arrangement into microfibrils allow water to move in and out of cell easily
31
Describe amino acids
Monomers that make up proteins. All amino acids have same basic structure, amino group at one end carbon in middle and acid group on other side. Each has a different r group. Some r groups are hydrophilic and some are hydrophobic
32
What are essential amino acids
Amino acids animals cannot build from materials they take into their body
33
Describe storage of amino acids
Animals cannot store excess amino acids as they are toxic when too much is present. Amino groups removed by process called deamination in the liver which is where the amino groups are converted into urea and removed in the urine
34
Describe the formation of peptide bonds
Condensation reactions occur between the acid group of one amino acid and the amino group of another, forming a covalent bond and a water molecule is produced. New bond formed called a peptide bond. Reverse is hydrolysis.
35
Define primary structure
The unique amino acid sequence of a polypeptide or protein
36
Define secondary structure
Formed when chains of amino acids coil or fold to form an alpha helix or beta pleated sheet. Hydrogen bonds hold the coil in place.
37
Define tertiary structure
The final 3d shape of a protein formed when the coils and pleats themselves coil or fold. A proteins tertiary structure is vital to its function
38
Define quaternary structure
Where a protein is made up of more than one type or polypeptide or a polypeptide and an inorganic compound eg haemoglobin
39
Describe collagen
Fibrous protein made of 3 polypeptide chains wound around each other like a twisted rope. Each chain is a coil made of amino acids. Hydrogen bonds form between the chains and this gives it strength. Each collagen molecule forms covalent bonds called cross links with other collagen molecules next to it. This results in a structure called a collagen fibril. Many fibrils together form a collagen fibre
40
Describe the functions of collagen
Cartilage and connective tissue. Tendons made of mostly collagen and they connect skeletal muscle to bones
41
Describe the 5 differences between haemoglobin and collagen
Haemoglobin is a globular protein and collagen is a fibrous protein. Haemoglobin has a wide range of amino acid constituents in its primary structure. Collagen has 35% of its primary structure is glycine. Haemoglobin contains a prosthetic group, haem. Collagen doesn't have a prosthetic group. Much of haemoglobin molecules are wound into alpha helix structures. Much of collagen molecules consist of left handed helix structures
42
Describe triglycerides
Mainly used as energy storage molecules, long hydrocarbon tails contain lots of chemical energy so lots of energy released when they're broken down. Insoluble so don't cause water to enter cells by osmosis which would make them swell. They bundle together as insoluble droplets in cells as tails are hydrophobic
43
Describe phospholipids
Make up bilayer of cell membranes which control what enters or leaves cells. Their heads are hydrophilic and their tails are hydrophobic so they form a double layer with heads on each side facing out towards water. Centre of bilayer is hydrophobic so membrane acts as a barrier to water soluble substances
44
Describe cholesterol
Help strengthen the cell membranes by interacting with phospholipid bilayer. Small size and flattened shape allow cholesterol to fit in between phospholipid molecules I'm the membrane. They bind to r hydrophobic tails of th phospholipids causing them to pack more closely together. This helps to make the membrane less fluid and more rigid
45
Draw a triglyceride molecule
Glycerol. 3 fatty acids make up hydrocarbon tail that makes lipids insoluble in water
46
Draw a phospholipid
Ionised phosphate group so attracts water molecules. Hydrophobic fatty acid tail of 2
47
Describe DNA
It's a polynucleotide and double stranded
48
Draw a DNA nucleotide
Phosphate group. Deoxyribose sugar. Varying nitrogen containing base
49
What are the DNA bases and which are which category
adenine and guanine are purines which are small. Thymine and cytosine are pyramidines which are bigger. A binds to t and g binds to c
50
Describe RNA
Polynucleotide. Sugar in RNA nucleotides is a ribose sugar. Nucleotides form a single strand and bases are uracil which is a pyramidine and adenine which is a purine
51
Explain the formation of DNA molecules
Two DNA strands run next to each other. Anti parallel because strands run in opposite directions. Bases join due to complimentary base pairing rules, a to t and g to c. Hydrogen bonds form between bases. In a complete DNA molecule the anti parallel chains twist to form a double helix structure.
52
Why is DNA replication said to be semi conservative
Each new DNA molecule consists of one original conserved strand and one new strand
53
How does DNA replication occur
Double helix untwisted. Hydrogen bonds between bases broken apart to unzip DNA exposing bases. Free DNA nucleotides are hydrogen bonded onto exposed bases by DNA polymerase following the base pairing rules. Covalent bonds are formed between the phosphate of one nucleotide and the sugar of another, sealing the backbone. This continues along the molecule until two new DNA molecules are formed, each an exact replica of the original due to complimentary base pairing
54
What is a gene
A sequence of bases on a DNA strand which make a code for a protein. They code for the sequence of amino acids I'm the protein. Each gene is on a specific place (locus) on a chromosome. Different versions of the gene are called alleles.
55
Describe protein synthesis
DNA carries instructions that make proteins but the organelles that make proteins (ribosomes) are in the cytoplasm! Oh no! The DNA is too obese (large really) to move out of the nucleus so sections of DNA are copied onto RNA which is like a little thin model instead. RNA leaves the nucleus nd joins with a ribosome in the cytoplasm where it can be used to synthesise a protein. So RNA and DNA are vital for living organisms to grow and develop.