Biology Topic 1 - DNA and Proteins

Study!!!

Why is DNA Protein Bound?

Because it wraps around a protein called a "Histone."

Whats the order of Structure in Proteins

Primary, Secondary, Tertiary, Quaternary

Whats the difference between the Lagging and Leading Strand?

The complementary nucleotides bind onto the...
Leading strand: by a smooth motion
Lagging Strand: by sections called "Okazaki Fragments."

What is DNA Replication considered as and why?

It is considered as Semi-Conservative, because the 2 molecules produced both have one strand which is newly synthesised and the other is an original strand.

What does the Helicase do?

In DNA Replication, it binds to the promoter region on the DNA Molecules and begins unzipping it into the lagging and leading strand by breaking the hydrogen bonds

What does DNA stand for?

Deoxyribonucleic Acid

What are the 4 Complementary Nitrogenous Bases

Adenine = Thymine
Guanine = Cytosine
(AT GC)

What are Introns?

They are non-coding regions on genes or mRNA

What are Exons?

They are coding regions on DNA and mRNA

The DNA Replication process continues until...

2 new DNA Molecules are fully synthesised.

How does a DNA turn into a Chromosome?

It tight wraps around positively charged histone proteins forming nucleosome, where it is then further coiled and condensed into a chromosome.

Describe the 3 Structural Properties of the DNA Molecule

1. Sugar Phosphate Backbone
2. Sugar bonds to the Nitrogenous Bases
3. Nitrogenous Bases are Complementarily bonded by Hydrogen Bonds

______ are segments of DNA

Genes

Where does Translation occur?

In the cytosol of the cell.

What occurs in splicing and why?

The immature strand turns into a mature strand as introns are spliced out as they do not code for proteins, whereas exons do.

What is the tRNA's purpose?

In translation, it reads the mature mRNA molecule and attaches its anticodons onto the codons of the mature mRNA molecule in a complementary fashion, placing specific amino acids in a specific order.What is the purpose of the RNA Polymerase

What is the purpose of the RNA Polymerase

It binds to the promoter sequence of the DNA Molecule before the gene, where it would unzip it into the Template and Coding strand. It would then also bind free floating nucleotides onto the template strand in a complementary fashion.

What is the process order in Gene Expression?

Transcription, Processing, then Translation

What binds to the mature mRNA and reads a start codon, and what does this initiate?

Small and Large ribosomal units bind to the mature RNA reading the start codon, which initiates the transcription process.

True or False? 
tRNA molecules create amino acids

False, as it comes with an amino acid already attached.

How is Translation stopped

When a stop codon is reached.

How is the mRNA molecule read?

from 5' to 3'

How is the amino acids in Translation formed into a chain, and what is that chainclled?

The amino acids are bonded together by peptide bonds, forming a polypeptide chain.

How does Transcription end?

This process continues until the termination region is met, and an immature mRNA molecule is produced. It would detach from the DNA Molecule and the DNA Molecule would rewind back together.

Why is specific protein folding so important in a 3D protein?

Because specific structure determines the active site/binding site, therefore it determines its function.

Whats the structure of a Secondary Protein

When folding occurs either through Alpha Helixes or Beta Sheets

What's the order of structure in proteins?

Primary, Secondary, Tertiary, Quaternary

What is the Tertiary Structure of a Protein

A fully formed folded 3D protein with peptide or hydrogen bonds 

What is the structure of a Primary Protein?

Single Linear Polypeptide Chain

What is a quaternary structure in a protein

2 or more fully polypeptide chains that are fully folded in a 3D structure.

What are 3 different Proteins

1) Enzymes
2) Proteins 
3) Hormones

What's an Anabolic Enzyme Reaction?

Where enzymes allow substrates to bind to its active sight in the correct orientation and alignment in a complemntary fashion forming an Enzyme substrate complex. This promotes bond formation with less energy required.

What is a Catabolic Reaction?

Substrate is binded in a complementary fashion to the enzyme active sight, where stress is placed onto the bonds of the substrate breaking it down. this allows the enzyme to breakdown with less energy required.

What do enzymes do?

Catalise a reaction

What are the 4 factors that impact Enzymes?

1) inhibitors
2) pH levels
3) Temperature
4) Concentration Levels

What are the 2 types of inhibitors and how do they impact enzymes?

Non-Competitive - Bind to the allosteric site of the enzyme, changing the active site shape which is no longer complementary to the specific substrate it was once complementary to.

Competitive - It races to bind to the active site of the enzyme before the substrate can, disabling the function of the enzyme to bind to the substrate.

What are the 2 aspects of an enzyme?

There is a specific substrate, where the ENZYME binds subtrates to its active sight to speed up a reaction catabolically or anabolically

How does temperature impact Enzyme function?

At lower temperatures it is suboptimal where less kinetic energy is present therefore slowing down the rate of collision between subtrate and enzyme. At just under optimal temperature, there is slightly less enzyme substrate collisions. At optimal there is an efficient amount of substrate and enzyme colliisons. However at extreme temperature, this causes the bonds between the enzyme to break denaturing the enzyme thus losing its function. 

What are the different forms of point mutations.

Insertion Deletion Substitution

What are the 2 types that stop gene expression and describe what they do

Methylation - Methyl groups bind to cytosine Bases or histones, making DNA innaccessible to transcription proteins thus preventing DNA from being expressed

Histone Modification - Acetyl groups are removed from histones making it too tightly packed, preventing transcription enzymes to read the DNA.

What are the 2 types of promoting gene expressions?

De-Methylation - Methyl groups are chemically removed from the cytosine bases allowing the transcription enzyme to read the DNA base pairs.

Acetylation - Acetyl groups are applied to the histones therefore balancing the charges, and thus making it less tightly packed and being able to be read by transcription enzymes.

What are point mutations and describe the different forms?

Where there is an alteration to the single base pair in DNA in the form of Missense or Nonsense. Missense is where it changes the amino acid incorporated into the protein changing the polypetptide chain, whereas nonsense is where a stop codon is introduced shortening the polypeptide chain. Silence is where the amino acid is not changed and frameshift is where a base pair is inserted and makes the whole frame of base pairs to shift.

What are mutations?

Mutations are changes to the DNA Sequence

What are epigenetics

Epigenetics are alters to the gene expression without changing the DNA sequence itself

Difference between mutations in Somatic and Germ cells

Germline mutations are inheritable, whereas somatic mutations are not inheritable.

Compare the function of tumour suppresor genes and onco genes.

Tumour suppresor genes prevent rapid cell division decreasing chances of cancer, whereas oncogenes promote rapid cell division which increases the chance of cancer

What is the intended outcome of PCR?

To synthesis and duplicate DNA from a small DNA sample.

Describe the 3rd step of PCR

Extending - The heat resistance DNA Polymerase begin binding free floating nuceotide to the base pairs on the exposed strand of the DNA molecule in a complementary fashion synthesising new DNA on the original sample. This process repeats until the DNA strand is amplified many times.

Describe the 2nd step of PCR

Annealing - Solution is cooled down to around 60 degrees celsius which allows primers to attach to the exposed DNA strand creating a starting the site for the heat resistant DNA polymerase.

Describe the 1st step of PCR

Denaturing - Solution is heated up to around 95 degress celsius which seperates the DNA Molecule into 2 strands by breaking the hydrogen bonds between DNA bases.