deck_3734989

Question 1

94% of living matter is composed from just 4 elements. name these elements.

Answer 1

1) carbon 2) oxygen 3) hydrogen 4) nitrogen - the other 4% is made up of calcium, phosphorus, potassium, sulphur, sodium, chlorine

Question 2

name the key molecular constituents of a cell.

Answer 2

1) Water (60-85% )2) proteins 3) nucleic acids 4) lipids 5) carbohydrates

Question 3

explain how the uneven distribution of electrons in the cloud influences its properties of H20.

Answer 3

1) O is more electro-negative that H , therefore the electrons that make up the bond between O and H are not shared equally - they are pulled towards the O2) as a result O has a slightly negative charge and H has a slightly positive charge. (polar solvent)3) so water can hydrogen bond4) water is a great solvent5) resists changes in temperature - in liquid water the hydrogen bonds between water molecules are fluid and constantly breaking and forming (dynamic)- hydrogen bonds stabilise protein interactions. water stabilises macromolecular interactions- water allows bonds to dissociate -Cytoplasm - water plus complex mixture of organic and inorganic compounds

Question 4

Define: 1) hydrophilic 2) hydrophobic

Answer 4

1) hydrophilic- having a tendency to mix with, dissolve in, or be wetted by water2) tendency of nonpolar substances to aggregate in aqueous solution and exclude water molecules-water loving readily associates with water. water hating molecules are insoluble - membranes: lipid bilayer formation driven by hydrophobic forces. energetically favourable , form spontaneously because it is composed of amphipathic phospholipids

Question 5

what is polymerisation?

Answer 5

a chemical process that combines several monomers to form a polymer. polymers are long molecules consisting of many similar or identical building blocks linked by covalent bonds - dehydration reaction is the synthesis of a polymer , water removed as each monomer is removed

Question 6

name the monomers for each of the following polymers:1) nucleic acid 2) proteins 3) carbohydrates 4) fatty acids

Answer 6

1) nucleotides 2) amino acids 3) sugars 4) Acetyl CoA

Question 7

what is the central dogma of molecular biology

Answer 7

DNA is transcribed into messenger RNA which is then translated into a protein - this is the process of gene expression

Question 8

Explain the role of proteins in the following cells:1) blood2) brain and nerves3) enzymes 4) antibodies 5) cellular construction workers 6) cellular messages 7) muscles 8) hair and nails (proteins make up 15% of a cells weight)

Answer 8

1) blood: the haemoglobin in protein carries oxygen in your blood to every part of your body 2) brain and nerves: ion channel proteins control brain signalling by allowing small molecules into and out of nerve cells 3) enzymes: in you stomach, saliva and small intestine are proteins that help you digest food4) antibodies- antibodies are proteins that help defend your body against foreign invaders such as bacteria and viruses 5) cellular construction workers: huge cellular clusters of proteins form molecular machines that do your cells heavy work. such as copying genes during cellular division and making new proteins. 6) cellular messages- receptor proteins stud the outside of your cells and transmit signals to partner proteins on the inside of the cells. 7) muscles - muscle proteins called actin and myosin enable all muscular movement 8) hair and nails- protein called alpha keratin forms your hair and finger nails.

Question 9

what happens when a protein is hydrolysed?

Answer 9

hydrolysis is the reverse of dehydration, breaks bonds between monomers by adding water molecules.

Question 10

Name two nucleic acid

Answer 10

1) Deoxyribonucleic acid (DNA) : - double stranded , inherited material 2) Ribonucleic acid (RNA):- single stranded, many different functions

Question 11

what holds the genetic code in DNA?

Answer 11

The nitrogenous bases. - pyrimidines= cytosine , guanine, uracil (RNA)- purines= adenine and guanine

Question 12

outline the difference between an nucleotide and a nucleoside

Answer 12

1) nucleoside : base + sugar 2) nucleotide: base + sugar + phosphate group. -nucleotide is the monomer unit of DNA

Question 13

describe the structure of a single DNA strand.

Answer 13

1) alternating phosphate- sugar backbone with projecting bases 2) the bases form hydrogen bonds between DNA strands. only certain combinations viable: A-T (U), G-C3) nucleic acid have polarity and are synthesised from 5’ to 3’, in a double strand they run in opposite directions relative to each other- Antiparallel

Question 14

DNA is replicated semi-conservatively, explain what this means.

Answer 14

two strands of DNA are separated and individually copied using each of the two old strands as a template. This forms two new double helices of DNA, each composed of one new strand and one original (or conserved) strand of DNA 1. This method ensured that both strands were accurate copies of the original

Question 15

outline the structure and function of RNA

Answer 15

1) Similar structure to single DNA strand.2) Ribose sugar rather than deoxyribose.3) Uracil rather than thymine.4) function:- protein synthesis : mRNA - messenger RNA, rRNA - ribosomal RNA & tRNA - transfer RNA- RNA splicing : snRNA - small nuclear RNA - Gene regulation : miRNA - micro RNA & siRNA – small interfering RNA

Question 16

Define the following :1) genome 2) genomics 3) Transcriptome 4) Transcriptomics5) Proteome6) Proteomics

Answer 16

1) Genome- the genome is the genetic material of an organism2) genomics- discipline in genetics that applies recombinant DNA, DNA sequencing methods, and bioinformatics to sequence, assemble, and analyze the function and structure of genomes3) the set of all RNA molecules, including mRNA, rRNA, tRNA, and other non-coding RNA transcribed in one cell or a population of cells.4) Transcriptomics the study of mRNA expression patterns.5) the entire set of proteins expressed by a genome, cell, tissue or organism at a certain time6) is the large-scale study of proteins, particularly their structures and functions.

Question 17

what is bioinformatics?

Answer 17

an interdisciplinary field that develops methods and software tools for understanding biological data.-Bioinformatics is the field of research which strives to make sense of all this data

Question 18

what is an amino acid?

Answer 18

Amino acids are biologically important organic compounds composed of amine and carboxylic acid functional groups, along with a side-chain specific to each amino acid.-There are 20 different amino acids.( 22 standard amino acids, 21 are found in eukaryotes, 20 are common and encoded by the universal genetic code)- protein sequences are made up of different combinations of amino acids.-glycine is the most simple amino acid with just an H atom as a side “chain”

Question 19

name some nonpolar amino acids

Answer 19

1) glycine 2) alanine 3) Valine 4) leucine 5) isoleucine 6) methionine 7) phenylalanine 8) tryptophan 9) proline

Question 20

name some uncharged polar amino acids

Answer 20

1) serine 2) threonine 3) cysteine (weakly polar)4) tyrosine 5) Asparagine 6) glutamine

Question 21

name some charged amino acids

Answer 21

acidic:1) aspartic acid 2) glutamic acid basic:1) lysine 2) arginine 3) histidine

Question 22

what is translation?

Answer 22

the synthesis of a polypeptide, using information in the mRNA- translated at ribosome to make proteins 1)RNA and mRNA join together and ezymes attatch a specific amino acid to one end of each tRNA (anticodons)2) next, the polypeptide chain is put together; the polypeptide chain continues to grow as the mRNA moves along the ribosome3) the ribosome reaches the stop codon and the newly made polypeptide falls off; the tRNA leaves the ribosome and the ribosome moves away from the mRNA

Question 23

define: triplet code

Answer 23

1) The triplet code of 4 letters gives 43 = 64 possibilities.2) Only code for 20 amino acids plus “start” and “stop” codes therefore a lot of redundancy3) Met (start) and Trp have single codes.4) RNA is read in triplets of bases called codons.Specific codons are used to encode a specific amino acid, or indicate the termination or initiation of translation

Question 24

what is transcription?

Answer 24

the process by which the genetic instructions in a specific gene are rewritten into an RNA molecule1) RNA polymerase binds to a promoter, a specific nucleotide sequence of DNA where RNA polymerase binds and initiates transcription2) then the RNA polymerase adds free RNA nucleotides on one of the DNA strands3) when RNA polymerase reaches a termination signal it releases the DNA and the newly formed RNA molecule

Question 25

a proteins function is determined by is specific structure. describe the four levels of protein structure

Answer 25

1) primary structure - this is the linear sequence of amino acids in the order in which they are joined by polypeptide bonds. (the sequence is written from the N (amino) terminus to C (carboxyl) terminus)2) secondary structure-3 main elements: Alpha helices, Beta sheets, random coil and protein disorder (intrinsically unstructured regions of proteins, may become ordered on binding)3) tertiary structure - the way the whole chain (including the secondary structures) folds itself into its final 3-dimensional shape. ( hydrogen bonds , hydrophilic and hydrophobic interactions)4) quaternary structure- the arrangement of multiple folded protein or coiling protein molecules in a multi-subunit complex.- a proteins structure is determined only by the sequence of amino acids

Question 26

describe how a peptide bond is formed

Answer 26

A peptide bond forms between the carboxyl group of one amino acid and the amino group of the adjacent amino acid. condensation reaction

Question 27

what are chaperone proteins?

Answer 27

1) proteins that assist the covalent folding or unfolding and the assembly or disassembly of other macromolecular structures2) proteins do not need chaperones to fold

Question 28

many proteins are composed of multiple domains. explain what domains are

Answer 28

1) Domains are regions of a protein with a discrete fold and/or function.2) These can be isolated away from the protein as a whole and will fold independently into an active conformation.3) Most proteins are found to be made up of a number of identifiable domains.4) Different combinations of domains give protein with unique properties.

Question 29

Why predict protein structures?

Answer 29

1) Bridge gaps in knowledge, coping with data deluge2) Fast, cheap, accurate! (Experimental methods are expensive and time consuming)3) Inform and direct experimental work4) Useful for mutagenesis studies5) Protein design - How will this protein fold?6) Some proteins are difficult to resolve experimentally e.g. intrinsic protein disorder, membrane proteins7) Understanding protein evolution8) Inferring function!