DNA & RNA Flashcards by Skye Cordon

Nucleotide

Consists of a sugar molecule attached to a phosphate group and a nitrogen base

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Gene expression

The process where information in a gene is used to make a product (protein)

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Transcription

The process by which mRNA is formed, using the code on a DNA strand (antisense) by matching the sequence of nucleotides

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Nitrogenous bases

Thymine
Guanine
Adenine
Uracil
Cystosine

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Messenger RNA

The RNA molecule that transfers coded information from the nucleus to ribosomes

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Intron

Non-coding sections of RNA transcript

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Exxon

Part of the RNA transcript that includes a section of the final piece of RNA after introns have been removed during RNA splicing

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Helicase

The enzyme responsible for the separation of DNA strands during replication

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Base triplet

A group of 3 nitrogenous bases on the DNA strand

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Template strand

The strand of DNA corresponding to the mRNA sequence

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Coding strand

Identical to the strand of mRNA being produced, but containing thymine instead of uracil

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Translation

The process occurring inside the ribosome, turning tRNA into amino acids, which then turn into protein

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Start codon

The first codon of mRNA translated by risbosomes - AUG

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Methionine

A hydrophobic amino acid

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Anticodon

A trinucleotide sequence, complimentary to that of a corresponding codon in mRNA

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Promoter sequence

Initiates the transcription of the first codon from a DNA triplet

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Terminator sequence

Signals termination of transcription to RNA polymerase

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RNA polymerase

The enzyme that transcripts DNA sequences into RNA

What are the 3 stages of translation

Initiation
Elongation
Termination

Initiation

mRNA enters the ribosome and tRNA anticodon binds to start codon (aug)

Elongation

More tRNA binds to the mRNA and attached amino acids bond together (peptide bond), forming a polypeptide chain. Initial tRNA breaks off.

Termination

When polypeptide is complete, a stop codon is recognised and a primary protein is formed.

Stop codon ( UAA, UAG, UGA)

Epigenome

a multitude of chemical compounds that tell the genome what to do. The epigenome is made up of chemical compounds and proteins that can attach to DNA and turn genes on and off

Methyl

Silence/turn off transcription

- Attach to cytosine at CG

Acetyl

Loosens interaction between DNA and histones, creating a larger surface are for translator enzymes to decode. Attach to amino acid lysine tail on histones

Can there be multiple codons for an amino acid?

Yes

What are the stages of mitosis

``` Ipmat- Interphase Prophase Metaphase Anaphase Telophase Cytokinesis ```

What are the characteristics of an active gene?

Wrapped loosely around his tone Few methyl molecules attached Many acetyl molecules Many mRNA transcripts

What are the characteristics of an inactive gene?

Gene wrapped tightly around histone Many methyl molecules attached Few acetyl molecules Few mRNA transcripts

What are the 3 ways variation can occur in a gene?

Via crossing over (division 1) Random alignment Independent assortment

What cells does mitosis occur in?

eukaryotic cells - a cell with a nucleus

What’s the sequence of events of DNA replication

- helicase splits DNA strands - Primase lays a primer segment on leading strand - DNA polymerase binds to primer and lays complimentary nucleotide bases to the original strand - primase primes fragments on lagging strand - polymerase adds bases in Okazaki fragments, working 5” - 3” - Exonuclease removes all primers from both stands - DNA polymerase fills in gaps - DNA ligase seals fragments, forming continuous strand

What’s helicase used for

Splits the DNA strands

What’s DNA polymerase used for?

Adds bases to DNA strands

What removes the primers from the DNA strand during DNA replication

Exonuclease

What’s a totipotent stem cell

Forms the embryo and it can give rise to any cell necessary for embryonic development.

Which stem cell is capable of becoming most but not all tissue cells in the human body?

Pluripotent

What’s a multipotent cell?

A cell with potential to form a number of different cells, specialised to their type. Eg. Stem cells in bone marrow make blood cells only - not muscle tissue/ bone tissue/ nervous tissue

Link stem cells to mitosis and gene expression

As cells undergo mitosis, different genes become activated due to its environment, in turn making cells specialised to a particular task. Stem cells can either undergo mitosis ( stochastic differentiation) or form specialised cells (both forms of differentiation)

Define differentiation in stem cells

When a cells environment impacts the activation and deactivation of certain genes, making the daughter cells specialised to a particular task

Definition of stem cell

- unspecialised cells - potential to give rise to diff. types of cells within the body - used for growth and repair

What are the two ways a stem cell can differentiate

- obligate asymmetric replication ( daughter cell) | - stochastic Differentiation (mitosis)

What are examples of post transcriptional modification

Poly-A-tail, guanine cap, RNA splicing

What are the 3 types of stem cells

Totipotent, pluripotent, multi potent