DNA TEAS 7

who mainly discovered dna

james watson and francik crick

what is DNA

deoxyribonucleic acid, storing genetic information in nucleus

what is a chromosome

A tightly coiled DNA molecule wrapped around proteins, found in the nucleus.

How many chromosomes do humans have?

46 n

When does DNA replication occur?

S phase of interphase

what does helicase do

unzip dna strand by breaking hydrogen bonds

primase

enzyme that adds RNA primers to tell dna polymerase where to start

What does DNA polymerase do?

Adds new DNA nucleotides to build a complementary strand.

what is the lagging strand?

The DNA strand that is replicated in short fragments in the opposite direction (okazaki fragments)

dna ligase

glues fragments together since primase keeps being added, no exact set point

What is the result of DNA replication?

Two identical double-stranded DNA molecules.

what is the point of dna replication

To make an exact copy of DNA so that
🧫 each new cell gets a full set of genetic instructions during cell division.

what are the enzymes of dna replication

helicase, primase, dna polymerase, ligase

what is central dogma

process of transcribing dna to mRNA translated to protein

transcription defintion

The process of making mRNA from DNA inside the nucleus.

intitiation

Enzyme RNA polymerase binds to a promoter region

What is a promoter region?

A section of DNA that tells enzyme RNA polymerase where to start transcription.

elongation

enzyme rna polymerase seperates dna strand and adds rna nucleotides

termination

enzyme RNA polymerase reaches a terminator sequence in the DNA and stops transcription. The mRNA strand is released, and the DNA goes back to its shape

what is made right after transcription

PRE MRNA

RNA splicing

introns are cut out of pre-mrna and exons are formed together to form mRNA

5’ cap

A modified nucleotide added to the beginning of pre-mRNA that helps it bind to the ribosome and protects it.

Poly-A tail

long chain of amino acids that are added to end of pre-mRNA to move from nucleus to ribosome

translation

building a protein in ribosome by reading Mrna

codon

A sequence of 3 mRNA bases that codes for 1 amino acid.

tRNA (transfer RNA)

Brings the correct amino acid to the ribosome. Has an anticodon that pairs with the mRNA codon.

anticodon

A set of 3 bases on tRNA that is complementary to the codon on mRNA.

summarize translation

trna comes with anticodon to codon and gives it its amino acid, forms a polypeptide chain of amino acids

Polypeptide chain

long chain of amino acids connected by peptide ponds, first start of forming a protein

Primary structure

polypeptide chain of emino acids

secondary structure

The chain starts to fold into shapes like alpha helices and beta-pleated sheets, held by hydrogen bonds.

tertiary structure

3d shape is functional,

Quaternary structure

Two or more polypeptide chains combine to make a functional protein (not all proteins reach this stage).

purines

Adenine (A) and Guanine (G) – the larger nitrogenous bases with 2 rings in their structure.

Pyrimidines

Cytosine (C), Thymine (T) (in DNA), and Uracil (U) (in RNA) – smaller nitrogenous bases with 1 ring.