Chapter 3- Biological Molecules and Chapter 4- Enzymes Flashcards

Question

Synthesis of peptides

Answer 1

Amino acids join when the amine and carboxylic acid groups connected to the central carbon atoms react. The r groups are not involved at this point. The hydroxyl in the carboxylic acid group of one amino acid reacts with a hydrogen in the amine group of another amino acid. A peptide bond is formed between two amino acids

Answer 2

Sequence in which the amino acids are joined. It is directed by information carried within DNA. The particular amino acids in the sequence will influence how the polypeptide folds to give the proteins final shape.The only bonds involved in primary structure are peptide bonds.

Answer 3

The oxygen, hydrogen and nitrogen atoms of the basic , repeating structure of amino acids interact. Hydrogen bonds may form within the amino acid chai, pulling it in to a coiled shape called an alpha helix. Can also form beta pleated sheets.

Answer 4

``` Folding of the protein into its final shape Interaction between r groups Hydrophobic and hydrophilic interactions Hydrogen bonds Ionic bonds Disulfide bonds ```

Answer 5

The association of two or more individual proteins called subunits

Answer 6

Requires addition of a water molecule

Answer 7

Compact water soluble and usually roughly spherical in shape. They form when proteins fold into their tertiary structure in such a way that the hydrophobic r groups on the amino acids are kept away from the aqueous environment

Answer 8

Red oxygen carrying pigment found in red blood cells Made up of four polypeptides Two alpha and two beta subunits Each subunit contains a prosthetic haem group Able to pick up oxygen

Answer 9

An enzyme which speeds up the breakdown of hydrogen peroxide

Answer 10

Formed from long insoluble molecules. This is due to the presence of a high proportion of amino acids with hydrophobic r groups in their primary structures. They contain a limited range of amino acids, usually with small r groups. Primary structure usually quite repetitive. They tend to make strong, long molecules which are not folded into 3D shapes.

Answer 11

A group of fibrous protiens present in hair, skin and nails. Contains many strong disulphides bridges

Answer 12

Fibrous protein found in elastic fibres. Elastic fibres are present in the walls of blood vessels and in the alveoli of the lungs.

Answer 13

Is another fibrous protien. It is a connective tissue found in skin, tendons, ligaments and the nervous system Has a strong rope like structure and is long.

Answer 14

A pentose monosaccharide A phosphate group A nitrogenous base

Answer 15

By phosphodiester bonds

Answer 16

Deoxyribose contains one less oxygen

Answer 17

Made up of two strands of polynucleotides coiled into a helix The two strands of double helix joined together by hydrogen bonds Run in opposite directions-anti parrallel

Answer 18

C and G 3 bonds | A and T 2 bonds

Answer 19

Cytosine and Guanine

Answer 20

Anadine and guanine

Answer 21

Ribose, U instead of A

Answer 22

One old strand, one new | Double helix is unzipped, the free dna nucleotides will pair with complimentary base pairs.

Answer 23

Breaks down the hydrogen bonds

Answer 24

Forms phosphodiester bonds

Answer 25

Measure of how much the rate of reaction increases with a 10 degrees rise in temperature.

Answer 26

As the temperature increases the vibrations increase until the bonds strain and then break. The breaking of these bonds results in a change in the precise tertiary structure of the protien. The enzyme has changed shape and is said to have been denatured.

Answer 27

Hydrogen bonds ams ionic bonds between amino acid r groups hold protiens in their precise 3D shape. A change in pH refers to a change in hydrogen ion concentration. More hydrogen ions are present in low pH acid environments and fewer hydrogen ions are present in high pH alkaline environments

Answer 28

A molecule that has similar shape to substrate of enzyme and can fit into active site Blocks the substrate from entering the active site The enzyme cannot carry out its function and is said to be inhibited

Answer 29

Inhibitor binds to the enzyme at a location other than the active site. Known as a allosteric site.

Answer 30

A non protien helper component in order to carry out their function as biological catalysts. They may transfer atoms or groups from one reaction to another in a multi step pathway or they may actually for, part of the active site of an enzyme

Answer 31

Required by certain enzymes to carry out the catalytic function

Answer 32

Form an important part of the structure of carbonic anhydrase an enzyme necessary for metabolism of CO2

Answer 33

The O takes a negative charge The two Hydrogens take a positive charge The hydrogens are attracted to other oxygens from other water molecules

Answer 34

Solvent Transport medium Coolant A habitat

Answer 35

``` Place sample in boiling tube Add an equal volume of benedict reagent Heat the mixture gently for 5 minutes A brick red precipitate forms if positive and reduces Cu2+ to Cu+ A blue precipitate forms if negative ```

Answer 36

Sucrose is an example | However if sucrose is heated with HCl first it is hydrolysed glucose and fructose which are both reducing sugars

Answer 37

A few drops of iodine dissolved in potassium iodide solution are mixed with a sample. If the solution changes from yellow/brown to purple/black starch is present

Answer 38

A piece of equipment used to quantitvely measure the absorbance, or transmission, of light by a coloured solution. The more concentrated the solution the more light it will absorb and less it will transmit.

Answer 39

Use biological components to determine the presence and concentration of molecules such as glucose Molecular recognition Transduction

Answer 40

Draw a pencil line on the chromatography plate about 2cm above from the bottom. Four equally spaced points are marked along the pencil line The amino acid solution is added to a spot on the pencil line using a capillary tube The three remaining marks were spotted with three known amino acids Plate was then placed into a jar containing the solvent. The plate was then left until the solvent was 2cm from the top The plate was then allowed to dry The plate is then sprayed with ninhydrn spray

Answer 41

DNA must code for a sequence of amino acids

Answer 42

A sequence of three bases, called a codon. Each codon codes for a amino acid A section of DNA which codes for a whole protien is known as a gene It is universal all organisms use this code

Answer 43

Stop codons Start codons Several codons code for same amino acid

Answer 44

When enzyme is produced in an inactive form. Precursor enzymes often have to undergo a change in shape to the tertiary structure, particularly to the active site , to be activated. This can be achieved by the addition of a co factor.

Answer 45

Keratin Elastin Collagen

Answer 46

Link many soluble tropoastin Makes a cross linked stable insoluble structure Able to stretch and recoil without breaking

Answer 47

Three polypeptide chains wound around each other forms a triple helix structure Every third amino acid in chain is glycine Many boyfriends bonds form between the polypeptide chains forming long quaternary proteins Produce strong fibers The r groups repel one another increasing stability

Answer 48

``` Sample mixed with ethanol Then water Shaken If white emulsion forms indicates present of lipid If remains clear negative ```

Answer 49

Bitter test 3cm of liquid sample mixed with an equal volume of sodium hydroxide 1% copper sulfate solution was then added a few drops at a time until the sample turned blue The solution was mixed and left to stand for five minuteman minutes