DNA Structure, Function, and Gene Expression in Biology

Nuclear DNA coiled around histones in a non-dividing cell.

Chromatin

Super-coiled chromatin in a dividing cell.

Chromosomes

Each body cell contains __ chromosomes in the nucleus at the start of division.

46

Homologous partner

Each chromosome has a

Nuclear DNA

inherited from both maternal (mother) and paternal (father) side.

Mitochondrial DNA

_________________ is found in mitochondria.

Mitochondrial

__________ DNA is inherited only through the maternal side.

Contains genes for production of enzymes involved in respiration.

Mitochondrial DNA

Mutation rate

Mitochondrial DNA has a faster ___________ than nuclear DNA.

Human ancestral migration

Mitochondrial DNA is used to study ____________.

Function of DNA

storing the information for the production of proteins that determines the structure and function of cells.

Genetic code

DNA contains the the instructions for making proteins.

Proteins

consist of 100 or more amino acids chemically joined together by hydrogen bonds.

There are __ different types of amino acids from which to build proteins.

20

Uses of proteins

membrane transport, hormones, enzymes, movement (actin and myosin), structural purposes, and defence (antibodies).

Nucleotide

The building block of DNA which consists of a phosphate group, deoxyribose sugar molecule, and nitrogen base.

In mRNA, _________ is repllaced with __________.

Thymine, Uracil

Double helix

DNA has a ___________ design, consisting of two strands twisted together.

Genetic code

the sequence of nucleotide bases in the DNA.

Transcription

The process by which mRNA is formed using the DNA code.

Helicase and RNA polymerase

makes the double strand DNA separate into two single strands.

DNA replication

The process by which DNA makes a copy of itself.

Translation

The process of synthesizing a polypeptide chain from mRNA code.

Amino acid coding

Each triplet on the DNA template strand codes for one specific type of amino acid.

RNA polymerase

The enzyme that transcribes the bases on the template DNA strand to make a complementary molecule of mRNA.

Base pairing rule

The rule that states C - G and A - U in RNA (no T in RNA).

Complementary mRNA

mRNA that is formed is complementary to the DNA template strand.

Non-coding sequences that are removed from the mRNA molecule so that it contains only exons.

Introns

Coding sequences that remain in the mRNA molecule after introns are removed, allowing for protein synthesis.

Exons

Codon

A group of 3 bases on mRNA that codes for one amino acid.

tRNA

contains three bases forming an anticodon and transports amino acids to the ribosome.

Anticodon

A sequence of three bases on tRNA that binds with the complementary bases of the codon on the mRNA.

Polypeptide chain

A chain formed by the bonding of amino acids during translation.

Protein folding

The process that results in a protein produced as a result of specific folding of one or more polypeptides.

Epigenetics

The study of phenotypic expression of genes, influenced by factors controlling transcription and translation.

Gene expression

The process where a section of DNA is transcribed into mRNA and then translated into an amino acid chain to form a protein.

Epigenetic modifications

Changes in gene expression that do not involve changes in DNA nucleotide base sequence.

Inheritable epigenetic changes

Epigenetic modifications that accumulate throughout a person's life and can be passed on to offspring.

Environmental agents

Factors such as stress, nutrition, and toxins that may cause epigenetic changes.

DNA acetylation

The addition of an [] group to histones, causing DNA to unwind and activating gene expression.

DNA methylation

prevents transcription of the DNA as RNA polymerase cannot progress.