Bio sac 1

What is the role of DNA in cells?

DNA carries genetic information that dictates cellular functions, reproduction, and the inheritance of traits.

What are the three components of a DNA nucleotide?

A nitrogenous base, a sugar, and a phosphate group.

What is complementary base pairing?

The process by which nitrogenous bases pair specifically; adenine pairs with thymine, and cytosine pairs with guanine in DNA.

Why are C–G base pairs more stable than A–T pairs?

C–G pairs have three hydrogen bonds, while A–T pairs have two, requiring more energy to separate.

mRNA (function)

mRNA serves as a template for protein synthesis, carrying genetic information from DNA to the ribosome.

mRNA (key features)

is single-stranded, contains uracil instead of thymine, and has a sequence that is complementary to the DNA template.

mRNA (location)

nucleus —> cytosol (ribosome)

tRNA (function)

tRNA transfers specific amino acids to the ribosome during protein synthesis, matching the amino acid with the corresponding codon on the mRNA.

tRNA (key features)

contains an anticodon that pairs with the mRNA codon, and carries a specific amino acid

tRNA (cell location)

cytoplasm at ribosome

rRNA (function)

forms structure of ribosome, helps catalyse the formation of peptide bonds during protein synthesis

rRNA (key features)

• Single-stranded RNA that folds into complex shapes

• Highly conserved sequences across species

• Part of ribosome subunits

• Very abundant

• Non-coding RNA

rRNA (location)

synthesised in nucleolus, combines with proteins to become subunits, then to cytoplasm to corm subunits (eukaryote)

made in cytoplasm (prokaryote)

prokaryote

a type of cell that does not have a nucleus or other membrane-bound organelles.

• Examples: bacteria and archaea.

eukaryote

s a type of cell that has a nucleus and other membrane-bound organelles.

• Examples: plants, animals, fungi