VCE Biology Unit 3 Area of Study 1.1

Flashcards on Nucleic Acids and Proteins

Nucleic Acids

Large molecules constructed by joining nucleotides to form a polymer; the genetic material of a cell.

Function of Nucleic Acids

The basic unit of inheritance, coding for the synthesis of proteins.

Nucleotide

A sugar with five carbon atoms (pentose sugar), a phosphate group, and a base containing nitrogen.

Nucleotides

Monomers that join to form a long single chain of nucleic acids.

Phosphodiester Bond

A covalent bond between the phosphate of one nucleotide and the pentose sugar of the next nucleotide.

DNA

A structure made of anti-parallel strands of nucleotides linked by hydrogen bonding between complementary base pairs.

Anti-parallel Strands

Parallel strands that run in opposite directions.

Complementary Base Pairing

Adenine (A) paired with Thymine (T) and Guanine (G) paired with Cytosine (C).

DNA

Deoxyribonucleic acid, double-stranded with deoxyribose sugar and bases Adenine, Thymine, Guanine, and Cytosine.

RNA

Ribonucleic acid, single-stranded with ribose sugar and bases Adenine, Uracil, Guanine, and Cytosine.

mRNA

Messenger RNA; carries the code for protein synthesis from the nucleus to the ribosome.

tRNA

Transfer RNA; carries a specific amino acid to the ribosome for protein synthesis.

rRNA

Ribosomal RNA; a structural component of the ribosome, the site of protein synthesis.

Enzymes

Proteins speed up and control chemical reactions.

Amino Acids

Monomers of a polypeptide chain.

Polypeptides

Long chains of covalently bonded amino acids.

Primary Structure

The order (sequence) of amino acids which comprise the polypeptide chain.

Secondary Structure

The way a polypeptide folds in a repeating arrangement (α-helices and β-pleated sheets).

Tertiary Structure

The polypeptide chain folded, coiled, or twisted into the protein’s functional 3D shape.

Quaternary Structure

Proteins that consist of two or more polypeptide chains joined together.

Denaturation

A structural change in a protein that results in the loss of its function.

Proteome

The complete set of proteins expressed within a cell, tissue, or organism at a certain time.

Enzymes

Biological catalysts, typically proteins, that speed up and control chemical reactions.

Gene

A sequence of DNA which is transcribed into RNA.

Promoter

Where RNA polymerase binds; the ‘starting point’ of transcription.

Coding Sequence (Exons)

The sequence of DNA that is actually transcribed into RNA.

Introns

Non-coding intervening sequences of DNA.

Terminator

Signals for transcription to stop.

Gene Expression

The process whereby the information coded for in genes is transcribed and translated to produce proteins.

Transcription

The process of copying DNA into mRNA, occurring in the nucleus of eukaryotic cells.

Translation

The process of reading the mRNA code at the ribosomes in the cytoplasm to assemble amino acids into a polypeptide.

Introns

The non-coding intervening sequences that are removed from pre-mRNA.

Exons

The expressing sequences that code for proteins; they are joined together to form mature mRNA.

Alternative Splicing

A process that increases the number of different proteins that can be produced from one gene by including or excluding particular exons.

Rough Endoplasmic Reticulum, Golgi Apparatus, Vesicles

Organelles that are part of the protein secretory pathway, allowing proteins made within a cell to be transported out of the cell.