biology exam revision

What are the components of an amino acid

Central carbon, Amino group, Sidechain (R group), Carboxyl group

What part of an amino acid is responsible for different proteins

R group

What are some of the functions of proteins

Enzymes

Hormones

Antibodies

What is the primary structure

Sequence of amino acids

What bond holds the primary structure together

Peptide bonds

What is the secondary structure

Folding of a polypeptide chain forming alpha helixes and beta pleated sheets

What bond holds the secondary structure together

Hydrogen bonds

Peptide bonds

What is the tertiery structure

Functional 3d globular structure

What bonds hold the tertiary structure together

Hydrogen bonds

Disulphide bonds

What is the quaternary structure

Proteins that are composed of two or more polypeptides tertiery structure

What bonds hold the quaternary structure

Hydrogen bonds

Which proteins have quaternary structure

Insulin

Haemoglobin

What is a protein

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

What is a polypeptide

A long chain of amino acids

What is a Proteome

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

Product of a genome

What is an enzyme

A tertiary protein that catalyses chemical reactions in living things

What is a monomer

A molecule that is the smallest building block of a polymer

What is a polymer

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

What is a peptide bond

The chemical bond linking two amino acids

What is a polymerisation reaction

The reaction of joining amino acids together to form a protein

What is a nucleic acid

polymer of nucleotides

What is DNA

A double-stranded nucleic acid chain containing deoxyribose sugars.

Where is DNA located in eukaryotes

Nucleus

Chloroplast

Mitochondria

What is RNA

A single stranded nucleic acid chain containing ribose sugars

What is a nucleotide

The monomer subunit of nucleic acids.

What are the bonds that join nucleotides together

Phosphodiester bonds

What is a nucleotide made of?

A nitrogen-containing base,

A five carbon sugar molecule (ribose in RNA and deoxyribose in DNA),

A five carbon sugar molecule (ribose in RNA and deoxyribose in DNA),

What is a gene

A section of DNA (usually codes for a protein)

What are the nitrogenous bases of RNA

A, C, G, U

What are the nitrogenous bases of DNA

A, T, C, G

How many hydrogen bonds are between A and T?

2

How many hydrogen bonds are between C & G?

3

What are some similarities between DNA & RNA

Both have A, G & C

Both have a phosphate group

Both have a pentose sugar

What are some differences between DNA & RNA

DNA is double stranded

DNA has thymine instead of uracil

DNA's pentose sugar has one less oxygen (deoxy - absence of oxy)

What is the function of mRNA

Carries genetic information from the nucleus to the ribosomes for protein synthesis

Where is mRNA produced

Nucleus

Where is tRNA produced

Nucleus

What is the function of tRNA

Delivers specific amino acids to the ribosomes to form polypeptide chain during translation

What is the function of an anticodon

Attaches to mRNA codon then allows for the corresponding amino acid carried by tRNA to be joined to the growing polypeptide chain

What is the function of rRNA

Serves as the main structural component of ribosomes

Where is rRNA produced

Nucleus

What is the genetic code

Series of rules that defines how genetic information is transcribed and translated

What does universal mean

When all organisms use the same codons to code for specific amino acids

What does unambiguous mean

When each codon is only capable of coding for one specific amino acid

What does degenerate mean

When multiple condons code for the same amino acid

What does non-overlapping mean?

When each triplet or codon is read independantly

What is the name given to a sequence of 3 nucleotides in DNA

Triplets

What is the name given to a sequence of 3 nucleotides in mRNA

Codon

What is the name given to a sequences of 3 nucleotides in tRNA

Anticodon

What is a start codon

Sequences that signals the beginning of translation

What is a stop codon

Sequence that signals the end of translation

What is the trp operon

Series of structural genes controlled by a common promoter and operator that works to produce tryptophan

Transcription of the trp operon will occur when...

RNA polymerase is attached to the promoter

What type of biomolecule is the trp operon

Nucleic acid

What is the survival advantage of trp operon

Tryptophan production requires lots of energy

The ability to turn tryptophan production on and off allows for energy to be conserved

What are the key regions of a gene

Promoter

Operator

Introns

Exons

Termination Sequence

What is a promoter

Section of a gene in which RNA polymerase binds and transcribes DNA

What is an operator

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

What is a termination sequence

Sequence of DNA that signals the end of transcription

What is transcription?

Process in which DNA is read and copied into mRNA

What is the process of transcription

1. RNA polymerase binds to the promoter region

2. DNA unwinds

3. RNA polymerase reads template strand and constructs pre-mRNA via complementary-based pairing

4. Uracil replaces thymine

5. RNA polymerase and pre-mRNA detach

What is the primary product of transcription

Pre-mRNA

What is another name for pre-mRNA

Primary transcript

What is translation?

The process in which information in the mRNA is read and converted into a polypeptide chain

What is the process of translation?

1. Ribosome binds to and reads the mRNA molecule. The start codon initiates translation

2. tRNA anticodons are complementary to the mRNA codons

3. tRNA brings the corresponding amino acids to the ribosomes

4. Via a condensation polymerisation reaction adjacent amino acids are joined together into a polypeptide chain until a stop codon is reached and the polypeptide is released

What is the primary product of translation

Primary protein

Where does translation occur

Ribosome

Where does transcription occur

Nucleus

Where does RNA processing occur

Nucleus

Which organisms undergo RNA processing

Eukaryotes

What is the difference between a prokaryotic and a eukaryote gene

Prokaryotic genes contain introns whereas eukaryotic genes do not contain introns

What is the difference between prokaryotic DNA and eukaryotic DNA

Prokaryotic dna is circular whereas eukaryotic dna is linear

Prokaryotic dna is found in the cytosol whereas eukaryotic dna is found in the nucleus

How does RNA processing affect protein expression

RNA processing can result in the formation fo any different mRNA strands from a single gene

What are exons

coding regions of DNA

What are introns

non-coding regions of DNA

What is RNA polymerase

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

What is RNA processing

Modification of pre-mRNA to mRNA so that it is useful in translation

What are the steps of RNA processing

1. The removal of introns and the splicing of exons

2. The addition of a 5' methyl-G cap and a 3' poly-A tail

What is the function of the 3' poly-a tail and 5' methyl-cap

Prevent mRNA strand from degrading

What is splicing

Removing introns from RNA and sealing exons together

What is alternative splicing

Splicing of exons

What happens as a result of alternative splicing

Production of different mRNA strands from the same strand of DNA

What does RNA processing allow

A larger proteome than genome

What is the primary product of RNA processing

mRNA

What is gene expression

The process of reading information stored within a gene to create a functional product (usually a protein)

What is a highly conserved gene

A gene that has remained unchanged throughout evolution

What is a structural gene

Gene responsible for producing proteins that form the structure or facilitate the functioning of an organism.

What is gene regulation

Control of gene expression by turning transcription on and off

What are the two types of genes involved in gene regulation

Structural gene

Regulatory gene

What is an example of a structural protein

Collagen

What is an example of a regulatory protein

Amylase

What is an example of an immunological protein

Antibodies

What are the stages of gene expression

Transcription

RNA Processing

Translation

What is a regulatory gene

Gene that controls the production of a protein by influencing the expression of other genes

What are the steps in the protein secretory pathway

1. Proteins are produced at ribosomes

2. Folded in the rough endoplasmic reticulum

3. Transported via transport vesicles to the Golgi apparatus

4. Modified and packaged by the Golgi apparatus into secretory vesicles

5. Exported from the cell via the process of exocytosis.

What is exocytosis

Process in which a vesicle fuses with the plasma membrane to release contents into the extracellular fluid

What is the process of exocytosis

1. Vesicle-containing secretory products is transported to the plasma membrane

2. The membrane of the vesicle fuses with the plasma membrane

3. The secretory products are released from the cell into the extracellular environment

What are the main organelles in the protein secretory pathway

Ribosomes

Rough ER

Golgi Apparatus

Transport & Secretory Vesicles

What is bulk transport

The transport of very large molecules in and out of the cell

What does a ribosome do

Synthesises proteins