Pre-VCE Biology (Genetics)

Cell Theory

Cells are the basic unit of life, All living things are made of cells, Cells came from pre-existing cells.

All Cells …

Are bound by a plasma membrane, contain cytosol, contain chromosomes, contain chromosomes.

DNA in a Prokaryotic

DNA is in the nucleotide region and is circular.

DNA in a Eukaryotic

DNA is in the nucleus and is linear.

Characteristics of a Prokaryotic

Generally smaller than a eukaryotic and do not continue a nucleus or membrane bound organelles.

Characteristics of Eukaryotic

Contains a nucleus and membrane.

Plasma Membrane

Surrounds cells and organelles. Controls the entry and exit of substances from one area to another.

Semipermeable

Allows some substances to cross but prevents the passage of others.

Roles of Protein ( Transport )

Trans-membrane protein help substances cross the plasma membrane.

Roles of Proteins ( Reception )

Receptors for signalling molecules.

Roles of Proteins ( Anchorage )

Connect inter cellular cytoskeleton to extracellular matrix.

Roles of Proteins ( Cell Identify )

Marks cells and self

Roles of Proteins ( Inter cellular joining )

Join Cells together and allow communication between cells.

Roles of Proteins (Enzymatic Activity )

Allows reaction to occur.

Differences in plant and animal cells.

plant cells possessing a rigid cell wall, chloroplasts for photosynthesis, and a large central vacuole, which are absent in animal cells

Function of cell membrane

Controls what enters and exits the cell.

Structure of cell membrane

contains phospholipids whichs heads face outwards and face the liquids while the tail faces inwards and there are protein molecules in different places around this layer of phospholipids.

Function of cholesterol in the membrane

Cholesterol acts as a fluidity regulator. At high temperatures it uses its rigid structure to interfere with phospholipid bi layer and make it more rigid decreasing fluidity and in lower temperatures cholesterol prevents phospholipids from packing too close together therefore increasing fluidity.

Function of lipids in the membrane

Lipids decide what comes in and out of the cell.

Role of mRNA

Transcript of the the specific DNA instruction.

Role of tRNA

Delivers the amino acids (protein synthesis)

Role of rRNA

Component of the ribosome.

Transcription

the genetic instructions from a specific segment of DNA (a gene) are copied into a messenger RNA (mRNA) molecule. This mRNA molecule then carries the code from the nucleus to the ribosome.

Translation

mRNA goes to ribosomes and they begin to read the mRNA strand but only begin copying when they confront a start codon. tRNA carries amino acids and connects anti-codons to their matching codon.

Genome

The sum total of the genes present in a cell or organism.

Gene

An inherited trait that is passed on by parents.

Allele

Variant of a gene represented by upper and lower case letters.

Genotype

Set of genes that an individual inherit es. Represented by 2 alleles.

Phenotype

Physical trait that is expressed because of the genotype.

Function of Golgi Body

modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles, acting as the cell's post office.