Everything in DNA and Genome

All key area

What happens in genomic sequencing

In genomic sequencing the sequence of nucleotide bases can be determined for individual genes and entire genomes

What are molecular clocks used to show

Molecular clocks are used to show when species diverged during evolution

What are personalised genomics

An individuals genome can be analysed to predict the likelihood of developing certain disease

Pharmacogenetics the the use of

Genome information in the choice of drugs

What is required to determine the genomic sequence of an organism

Computer programmes and statistical analysis (bioinformatics)

Scientists compare the DNA base sequences of two different species and find that the sequences are very similar.

What does this suggest about the evolutionary relationship between the two species

That they last shared a common ancestor recently

Name the units of DNA

Nucleotide

What types of bond formed between bases

hydrogen bonds

Name the protein the help stores chromosomes inside a nucleus

Histones

Why is yeast considered a special example of a eukaryotic

It contains plasmids

Name given to additional DNA mainly found in bacteria cells

Plasmids

Why is yeast considered a special example of a eukaryotic

It contains plasmids

A DNA nucleotide contains three components.

State the three components

Deoxyribose sugar, phosphate, base

Name the type of bond that holds the paired bases together

Weak hydrogen bonds

Name the molecule present at the 5’ ends of a DNA strand

Phosphate

State two features of the organisation of DNA in a prokaryotic cell

Single circular chromosomes in the cytoplasm and additional circular DNA call plasmids

What are the examples of the cells in PROKARYOTIC

Bacteria

What are the examples of the cells in EUKARYOTIC

Plant, animal and fungal

Compare one different in the organisation of DNA in prokaryotic and eukaryotic cells

Eukaryotes have a linear chromosomes whereas prokaryotes have a single circular chromosome

State one location, other than the nucleus, where DNA can be

found in a eukaryotic cell

Mitochondria

How are nucleotides joined together within a single strand of DNA

Sugar phosphate backbone

Describe the arrangement of a DNA molecule.

Two strands of DNA nucleotides which are antiparallel. One strand runs in a 5’ to 3’ direction and the other strand runs in a 3’ to 5’ direction

Name of the enzyme that replicates strands of DNA

DNA polymerase

Name of a molecule that must be present for DNA replication to take place

Primers

Give one practical of PCR

Forensic science

During PCR the sample is heated to around 95°C. State what happens to the DNA at this temperature

Hydrogen bonds between bases are broken and strands of DNA are separated

During PCR, the temperature is lowered to approximately 50-60°C after the DNA strand have separated. State what happens at this stage

Primers to anneal to their complementary target sequences

Explain why a heat tolerant DNA polymerase is required during PCR

So it doesn’t denature due to high temperature used in PCR

During PCR, DNA is heated to between 70-80°C. State what happens at the DNA at this temperature

For heat tolerant DNA polymerase to replicate the region of DNA

State the role of primers during PCR

Indicates a starting point for DNA polymerase to being replication

State on commercial use of PCR

Settle paternity suits

State what happens after the heat tolerant DNA polymerase to replicate the region of DNA

The cycle continues to increase the number of copies of DNA

State the role of DNA ligase during DNA replication

Joints the fragments together in the lagging strand

State the role of the DNA polymerase during DNA replication

Adds complimentary nucleotide in a 5’ to 3’ direction

What is the definition of a template strand

Original strand of DNA that will be copied during the process

What is the definition of free nucleotides

A supply of nucleotides containing different base. Attached to the replication strand by DNA polymerase

Explain why primers are necessary for DNA replication

To give DNA polymerase a start point for replication

Explain why only the lagging strand can be replicated continuously

DNA polymerase replicates in a 5’ to 3’ direction

Name the enzyme that joins fragments together in the lagging strand

DNA ligase

Explain why DNA polymerase extracted from human cells would not replicate DNA in PCR

DNA polymerase extracted would be denatured

Describe the process of transcription

RNA polymerase creates a complementary strand of mRNA from the DNA template producing a primary transcript

Describe the role of tRNA during translation

Carries a specific amino acid to the ribosome

Explain how the base sequence of a gene determines the amino acid sequence of a protein

Three bases on mRNA are codons these codons will code for a specific animo acid

Describe the structure features of tRNA

tRNA has anticodon and animo acid attachment site

State what is meant by an intron

A non coding region of DNA

State what it meant by an exon

A coding region of DNA

Name the process that the mature transcript during translation

RNA splicing

State the function of messenger RNA (mRNA)

Carries a complementary copy of DNA from the nucleus to a ribosome

State the role of mRNA in gene expression

Carries a complementary copy of DNA from the nucleus to a ribosome

State the role of tRNA in gene expression

Carries a specific amino acid to the ribosome

State the role of rRNA in gene expression

Makes up parts of the ribosome along with proteins

Name of the enzyme that breaks bonds between bases in DNA during transcription and synthesises mRNA

RNA polymerase

How different forms of proteins be made from on gene

Alternative RNA splicing

What are the two stages of gene expression

Transcription and translation

What at the bases in RNA

Adenine, uracil, guanine, cytosine

Explain how alternative RNA splicing can allow different proteins to be produced from the same gene

Different combinations of exons are retained in the mature transcript

During RNA splicing, what happens to introns

They are removed from the primary transcripts

During RNA splicing, what happens to exons

They are retained and joined together to form the mature transcript

Name the process in which mRNA is produced from a DNA template

Transcription

Describe what happens to the primary transcript during RNA splicing

Introns are removed, while exons are joined together to form a mature transcript.

State the type of bond that joins amino acids together in a protein

Peptide

Describe the process of alternative RNA splicing

Different exons are joined together in the mature transcript

Definition of cellular differentiation

It’s the process by which a cell expresses certain to produce proteins characteristic for that type of cell

Cells in multicellular organisms contain the same genes but can become specialised

Explain how differential gene express produces different cell types

Different proteins will be expressed which are characteristics of different cell types

More cells in an organism contains the same genes. Explain why different types of cells produce different proteins and carry out different functions.

Different genes are expressed which are characteristic of specific cell types

State one way that stem cells can be used in scientific research

Testing new drugs

State what it meant by cell differentiation

The process by which an unspecialised cell becomes specialised to carry a particular functions by expressing certain genes

Explain why different types of specialised cells can have different structure even though they contain the same jeans

Express specific genes characteristic of specific cell types

State what is meant by a stem cell

An unspecialised cell that can differentiate into specialise cells

Differentiation in plants

Plants have meristems which are region of unspecialised cells that can divide

Differentiation in animals

Stem cells are unspecialised cell in animals that can divide

What are the two stem cells of animals

Embryonic and tissue

What are embryonic stem cells

They are cells that can differentiate into any of the cell types that make up the organism

What are embryonic describe as

Pluripotent

what are tissue stem cells

They are involved in the growth repair and renewal of cells found in that tissue

What are tissue stem cells describe as

Multipotent

What is ethical issues

They are embryonic stem cells that can offer effective treatment for disease and injury

What can therapeutic uses stem cells involve

Repair of diseased organs

Finnish the sentence

Each type of human cell has a different structure and function because

Only some of their genes are expressed

New meristem cells would form in addition to shoots.

Name the process responsible for this

Mitosis

Describe a property of embryonic stem cells which makes them useful for research

Can differentiate into any cell type

Suggest an ethical reason why medical research may involve the use of embryonic stem cells

Reduces animal testing

Describe how unspecialised cells in the meristem differentiate into specialised cells

Certain genes can be expressed

What is the definition of genome

The genome of an organism is its entire hereditary information encoded in DNA

Composition of the genome

A genome is made up of genes and other DNA sequences that do not code for proteins

Function of the genome

DNA sequences that code for protein are defined as genes

State what is meant by a gene

A section of DNA that codes for a protein

Most of the eukaryotic genome is non-coding. State two possible roles or

outcomes of non-coding DNA sequences

Regulate transpiration and can be transcribed but not translated such as rRNA and tRNA

Name two types of RNA produced from DNA that are not translated into protein

tRNA and rRNA

State one possible role of non-coding regions of DNA

Transcribed into rRNA

Definition of mutations

Mutations are change in the DNA that can result in no protein or an altered protein being synthesised

Two type of mutations are

Single gene and chromosome

Definition of single gene mutations

Single gene mutation involve alteration of DNA nucleotide sequence as a result of the substitution, insertion or deletion of nucleotides

Definition of substitution mutation

Nucleotide substitution is when one base is substituted for another in the DNA sequence

Three types of substitution mutations are

Missense, nonsense, splice site

What can missense mutations result in

Result in one amino acid being changed for another. This may result in non functional protein or have little effect on the protein

What can nonsense mutations result in

Result in a premature stop codon being produced which results in a shorter protein

What can splice site mutation result in

Result in some introns being retained and some exons not being included in the mature transcript

What can substitution be described as

A point mutation as it only affects one point of the protein

Definition of insertion in frameshift mutation

When a nucleotide is inserted into the sequence