Key Knowledge 1 Flashcards

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1
Q

protein

A

a biomacromolecule made of amino acid chains folded into a 3D shape

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2
Q

polypeptide 

A

a long chain of amino acids. Proteins can be made of one or many polypeptides

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3
Q

proteome 

A

all the proteins that are expressed by a cell or organism at a given time

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4
Q

enzyme 

A

an organic molecule, typically a protein, that speeds up specific reactions

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5
Q

carboxyl group 

A

the functional group on amino acid molecules that contains a hydroxyl group (OH) and an oxygen doublebonded to a carbon atom

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6
Q

what does an amino acid consist of

A

a central carbon atom that is bonded to a hydrogen atom, a carboxyl group (COOH), an amino group (NH2), and an R-group

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7
Q

amino group 

A

the functional group on amino acid molecules that is made up of one nitrogen and two hydrogens (NH2)

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8
Q

R-group 

A

the variable portion of an amino acid molecule. It can be one of twenty variations and determines the identity of the amino acid

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9
Q

R-groups chemical properties and example

A

can affect how different amino acids within a protein interact with each other.
For example, an amino acid with a hydrophobic R-group is more likely to form bonds with other hydrophobic R-group amino acids than it would with an amino acid containing a hydrophilic R-group.

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10
Q

monomer 

A

a molecule that is the smallest building block of a polymer

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11
Q

polymer 

A

a large molecule that is made up of small, repeated monomer subunits

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12
Q

condensation reaction

A

a reaction where two monomers join to form a larger molecule, producing water as a by-product

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13
Q

peptide bond 

A

the chemical bond linking two amino acids

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14
Q

where does the joining of amino acids together occur?

A

cell’s ribosomes via condensation reaction

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15
Q

primary structure 

A

the first level of protein structure, which refers to the sequence of amino acids in a polypeptide chain

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16
Q

secondary structure 

A

the level of protein structure where the amino acid chain forms either alpha-helices, beta-pleated sheets, or random coils

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17
Q

tertiary structure 

A

the functional 3D shape of a polypeptide chain

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18
Q

quaternary structure 

A

the level of protein structure where multiple polypeptide chains bond together, or other non-protein groups are added to form a fully functional protein

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19
Q

nucleic acid 

A

the class of macromolecule that includes DNA and RNA. All nucleic acids are polymers made out of nucleotide monomers

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20
Q

Every nucleotide includes

A

• a phosphate group
• a five-carbon (pentose) sugar
• a nitrogen-containing base.

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21
Q

5 carbons

A

first carbon being labeled 1’ (one prime) and the last carbon being labeled 5’ (five prime). The three carbons of particular interest include:
• 1’ which attaches to the nitrogenous base
• 3’ which attaches to the phosphate of the following nucleotide
• 5’ which attaches the five-carbon sugar to the phosphate group of the nucleotide.

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22
Q

DNA (deoxyribonucleic acid)

A

a double-stranded nucleic acid chain made up of nucleotides. DNA carries the instructions for proteins which are required for cell and organism survival

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23
Q

RNA (ribonucleic acid) 

A

a single stranded nucleic acid chain made up of nucleotides. Includes mRNA, rRNA, and tRNA

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24
Q

phosphodiester bond 

A

a strong covalent bond linking a five-carbon sugar to a phosphate group

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25
Q

sugar-phosphate backbone

A

a strong covalently linked chain of five-carbon sugar molecules and phosphate groups in a nucleic acid chain

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26
Q

gene 

A

a section of DNA that carries the code to make a protein

27
Q

genome 

A

the complete set of DNA housed within an organism

28
Q

antiparallel 

A

a characteristic of DNA strands describing how each strand runs in an opposite direction to the other. One strand runs in a 3’-5’ direction and the other runs in a 5’-3’ direction

29
Q

complementary base pairing

A

describes which nucleotides can form hydrogen bonds with each
other. C pairs with G, A pairs with T (or U in RNA)

30
Q

messenger RNA (mRNA) 

A

Carries genetic information from the nucleus to the ribosomes of the cell

31
Q

transfer RNA (tRNA)

A

Delivers amino acids to the protein synthesis site

32
Q

ribosomal RNA (rRNA)

A

RNA that is a key structural component of ribosomes, which assemble proteins

33
Q

transcription

A

-DNA unwinds/unzips
- RNA polymerase catalyses transcription through the joining of complementary RNA nucleotides
- transcription of the DNA template strand into pre-mRNA occurs
- pre-mRNA is complementary to the DNA template strand
- In pre-mRNA, A pairs with U

34
Q

translation

A
  • ribosome binds to and reads mRNA molecule
  • tRNA anticodons are complementary to the mRNA codons
  • tRNA brings the corresponding amino acids to the ribosome
  • adjacent amino acids are joined together in a polypeptide chain via condensation reaction
35
Q

triplet 

A

the sequence of three nucleotides in DNA coding for one amino acid

36
Q

codon 

A

the sequence of three nucleotides in mRNA coding for one amino acid

37
Q

genetic code 

A

the set of rules by which information is encoded in genetic material

38
Q

Properties of the genetic code

A

Universal- nearly all living organisms use the same codons to code for specific amino acids.

Unambiguous- each codon is only capable of coding for one specific amino acid. For example, the codon UUA only codes for the amino acid leucine.

Degenerate- while each codon only codes for one amino acid (unambiguous), each amino acid may be coded for by multiple different codons (degenerate). For example, both the codons UUA and UUG code for the amino acid leucine. This provides a degree of redundancy, where changes to the original DNA sequence through mutations may not necessarily lead to the insertion of different amino acid.

Non-overlapping- Each triplet or codon is read independently, without overlapping from adjacent triplets or codons

39
Q

regions of genes

A

Promoter
Introns
Exons
Termination sequence
Operator

40
Q

Promoter

A

the sequence of DNA to which RNA polymerase binds

41
Q

RNA polymerase

A

the enzyme responsible for constructing a pre-mRNA sequence from a DNA sequence during transcription

42
Q

introns 

A

non-coding regions of DNA that do not code for proteins. They are spliced out during RNA processing

43
Q

exons

A

regions of DNA that code for proteins and are not spliced out during RNA processing

44
Q

termination sequence

A

a sequence of DNA that signals the end of transcription

45
Q

operator

A

a short region of DNA that interacts with repressor proteins to alter the transcription of an operon

46
Q

repressor protein 

A

a protein coded for by a regulatory gene that prevents gene expression by binding to its operator

47
Q

gene expression 

A

the process of reading the information stored within a gene to create a functional product, typically a protein

48
Q

precursor messenger RNA (pre-mRNA)

A

the immediate product of transcription of a DNA sequence. Requires modifications before it can undergo translation

49
Q

ribosome 

A

an organelle made of rRNA and protein that is the site of protein synthesis. Can be free in the cytosol or attached to the rough endoplasmic reticulum

50
Q

5’ methyl-G cap and 3’ poly-A tail 

A

a molecule added to the 5’ end of pre-mRNA during RNA processing

a chain of adenine nucleotides added to the 3’ end of pre-mRNA during RNA processing

51
Q

splicing 

A

the process where introns are cut out of a pre-mRNA molecule, and exons are joined together

52
Q

spliceosome 

A

the enzyme that removes introns from the pre-mRNA molecule and joins exons together during RNA processing

53
Q

alternative splicing 

A

the process where different exons may be spliced, resulting in a single gene producing multiple different mRNA strands

54
Q

gene regulation 

A

the control of gene expression, typically achieved by switching transcription on or off

54
Q

structural gene 

A

a segment of DNA that doesn’t code for regulatory proteins, but instead codes for proteins that play a role in the structure or function of a cell or organism

55
Q

regulatory gene 

A

a segment of DNA responsible for producing proteins that control the expression of other genes

56
Q

operon 

A

a cluster of linked genes that all share a common promoter and operator and are transcribed at the same time

57
Q

conformational change 

A

a change in the three-dimensional shape of macromolecules such as proteins

58
Q

Ribosome in protein secretory pathway

A

Synthesises proteins. The ribosomes are the sites of protein synthesis. They assemble polypeptide chains from amino acids by translating mRNA.

59
Q

Rough endoplasmic reticulum

A

Folds and transports proteins. If a protein is destined to be secreted, the ribosome synthesising it is usually attached to the rough endoplasmic reticulum rather than being free in the cytosol. The environment inside the rough endoplasmic reticulum allows for the correct folding of the newly formed polypeptide chain before being passed to the Golgi apparatus.

60
Q

Transport vesicle

A

Transports proteins A transport vesicle containing the protein buds off the rough endoplasmic reticulum and travels to the Golgi apparatus. The vesicle fuses with the Golgi membrane and releases the protein into its lumen.

61
Q

Golgi apparatus

A

Modifies and packages proteins Proteins can have chemical groups (e.g. sugar molecules) added or removed at the Golgi apparatus, where they are often packaged into secretory vesicles for export or released directly into the cytosol for use by the cell.

62
Q

Secretory vesicle

A

Transports proteins Secretory vesicles containing proteins for export bud off the Golgi apparatus and travel through the cytoplasm, fusing with the plasma membrane. This releases the proteins contained from within, into the extracellular environment through the process of exocytosis.

63
Q

RNA Processing

A

Adding of the poly-A tail and methyl-G cap enables the mRNA to bind to the ribosomes in translation and also makes it more stable. Removal of the introns.