Biology & Its Themes

What is biology?

The scientific study of life

Response to the environment

Organisms detect and react to stimuli from their surroubdings

Regulation

Organisms control their internal conditions (e.g. body temperature, blood sugar etc)

Evolutionary adaption

Traits that suit organisms to their environment evolve over many generations

Ecosystem

All the living things in an area, together with the non-living environment they interact with. Abiotic and biotic factors interacting together

Community

All the different species living together in one ecosystem

Population

All the individuals of one species living in a specific area

Organism

A single individual living thing

Organ

A body part built from several tissues that carries out specific functions (e.g. leaf, heart)

Tissue

A group of similar cells working together to perform a specific function

Cell

The smallest unit of life able to carry out all of life's basic functions

Organelle

A membrane-bound structure inside a eukaryotic cell with a specific job (e.g. nucleus, chloroplast)

Molecule

Two or more atoms bonded together

Cell theory

All living things are made of cells , the basic unit of life

Prokaryotic cell

A cell with no nucleus and no membrane-bound organelles (Bacteria and Archaea)

Eukaryotic cell

A cell with a nucleus and membrane-bound organelles (plants, animals, fungi, protists)

Which domains are prokaryotic?

Bacteria and Archaea

Chromosome

A structure made of DNA (with protein) that carries an organism's genes

Gene

A section of DNA that codes for a specific protein or RNA

DNA Structure

Two strands of nucleotides (A, T, C, G) twisted together into a double helix

Genome

An organism's complete set of genetic instructions (all of its DNA)

Gene expression

Using the information in a gene to make a protein or RNA, via transcription then translation

Transcription

Copying a gene's DNA sequence into a molecule of mRNA.

Translation

Building a protein from the sequence carried by an mRNA molecule

Genomics

The study of whole sets of genes/DNA, rather than one gene at a time

Proteomics

The study of the full set of proteins made by a cell or organism

Producers vs consumers

Producers make their own food (e.g.photosynthesis); consumers get energy by eating other organisms

Energy flow in ecosystem

One-directional: energy enters mainly as light and leaves as heat

Feedback regulation

A process where the output of a pathway controls the same pathway

Positive feedback

A respond that amplifies the original stimulus (e.g. Blood clotting, Labour)

Binomial nomenclature

Naming a species: genus + species

What defines domain eukarya?

Its organisms nave eukaryotic cells (a nucleus &membrane-bound organelles)

Four subgroups of domain eukarya

Kingdom plantae, kingdom fungi, kingdom animalia, protists

Nutritional differences: Plantae, Fungi, Animalia

Plants photosynthesise, fungi absorb nutrients from surrounding, animals eat and digest other organisms

Unity in diversity

Very different organisms can share the same basic structures, e.g. cilia have the same architecture in Paramecium and human cells.

Adaptation (evolutionary)

A heritable trait that helps an organism survive and reproduce in its environment

Speciation via natural selection

Isolated populations adapt differently to their own environments, over time become separate species