DNA and protein synthesis

What is DNA, and where is it found?

DNA (deoxyribonucleic acid) is a molecule that carries genetic information. It is found in the nucleus of cells, contained within chromosomes.

What is the structure of DNA?

DNA has a double helix structure, meaning two strands are twisted around each other. It is a polymer made up of repeating units called nucleotides, which consist of a sugar (deoxyribose), a phosphate group, and one of four bases base. the sugar and phosphate group form a sugar phosphate backbone

What are the four bases in DNA and how do they pair?

The four bases are adenine (A), thymine (T), cytosine (C), and guanine (G). They follow complementary base pairing:

• A pairs with T

• C pairs with G

This is held together by weak hydrogen bonds.

What is a gene, and how does it relate to chromosomes?

A gene is a section of DNA that codes for a specific protein. Genes are located on chromosomes, which are long strands of DNA found in the nucleus. Humans have 23 pairs (46 total) chromosomes.

What is a genome?

A genome is the entire set of genetic material in an organism

what was the human genome project

the project that mapped all human genes

what things/ benefits does the human genome project do

1. allows us to understand genetic diseases

2. allows us to identify genes linked to certain diseases

3. helps us to track the migration of our ancestors

How does DNA control the production of proteins?

DNA contains instructions for making proteins. It does this through transcription and translation, where the genetic code is copied and used to assemble amino acids into proteins.

why must the base code sequence of DNA be copied before translation

because a whole DNA strand is too big to leave the nucleus so if we want to use a gene to make a protein we must make a copy of that protein first

list three things about the structure of mRNA compared to DNA

1. much shorter than DNA

2. only a single strand ( so not double stranded like DNA)

3. instead of containing the base T it contains the base U

explain the process of transcription

1. DNA unwinds to expose the base code sequence of the DNA template strand

2. the base code of each gene is transcribed onto the mRNA strand via the complementary base pairings

3. the mRNA then leaves the nucleus and goes to the ribosome

explain the process of translation

1. tRNA (transfer RNA) molecules bring amino acids to the ribosomes.

2. The anti codon on each tRNA molecule is complementary to the codons on the mRNA strand.

3. So the tRNA molecule binds to the codons on the mRNA strand and brings the corresponding amino acid to match the base code sequence on the mRNA codons.

4. The amino acids are joined together in a specific order via peptide bonds to form a polypeptide .

5. The polypeptide then folds to form a protein that can perform its function in the cell.

What is a mutation?

A mutation is a change in the DNA base code sequence. It can affect the structure of a protein and lead to diseases like cystic fibrosis or cancer, though most mutations have no effect.

How does DNA cause variation in organisms?

Differences in DNA base code sequences lead to variations in proteins, affecting traits like eye color, height, and susceptibility to diseases.