DNA Structure, Function, and Protein Synthesis

A set of flashcards covering DNA structure, gene organization, cell differentiation, and the steps of protein synthesis, formatted as questions with their corresponding answers.

What does DNA stand for?

Deoxyribonucleic Acid

What is DNA made of?

Nucleotides composed of a sugar, a phosphate group, and a nitrogen base

What are the four nitrogen bases in DNA?

Adenine (A), Thymine (T), Cytosine (C), and Guanine (G)

Which nitrogen bases pair together in DNA?

Adenine pairs with Thymine, and Guanine pairs with Cytosine

What is the shape of DNA?

A double helix

What is a gene?

A segment of DNA that codes for a specific protein

What is the hierarchy of genetic structure from smallest to largest?

Base → Nucleotide → Gene → DNA → Chromosome

How many chromosomes do humans have?

46 chromosomes (23 pairs)

Where is DNA stored in a cell?

In the nucleus, as chromatin or chromosomes

What is cell differentiation?

The process by which stem cells become specialised cells

Are all cells in a multicellular organism genetically identical?

Yes, but they express different genes

What determines a cell's function?

Its structure and the specific genes it expresses

Give three examples of specialised animal cells.

Sperm cells, red blood cells, and nerve cells

Give two examples of specialised plant cells.

Palisade cells and root hair cells

What are proteins made of?

Chains of amino acids called polypeptides

Where do amino acids come from?

They are obtained from the food we eat when dietary proteins are broken down

What is the process of making proteins called?

Protein synthesis

What are the two main steps of protein synthesis?

Transcription and translation

Where does transcription occur?

In the nucleus

Which enzyme unwinds the DNA during transcription?

Helicase

What does RNA polymerase do?

Builds the mRNA strand from the DNA template

What is the purpose of mRNA?

To carry genetic information from DNA to ribosomes

Where does translation occur?

At ribosomes in the cytoplasm

What is the role of tRNA during translation?

It brings specific amino acids to match codons on the mRNA

What is formed at the end of translation?

A polypeptide that folds into a functional protein

How does DNA differ from mRNA?

DNA is double-stranded, uses A-T-C-G bases, and remains in the nucleus; mRNA is single-stranded, uses A-U-C-G bases, and travels to the cytoplasm