Unit 1

Cell Theory states: • All organisms are made up of one or more cells. • All cells come from pre-existing cells. • The cell is the basic unit of life.

Metabolism refers to all the chemical reactions an organism uses to take in and transform energy from the environment.

plants convert solar energy into chemical energy via photosynthesis. • fungi and worms take in decaying matter and break down the chemical energy stored in those molecules to provide energy for growth and life. • Mammals change the chemical energy stored in plants and other animals into a form of energy called ATP that their cells can use.

Hereditary information can be transferred to offspring in one of two ways. • Sexual reproduction • Two parents supply the DNA • Hereditary information recombines from two organisms of the same species. • This occurs in most plants and animals • Asexual reproduction • A single parent supplies DNA • Original and new organisms are genetically the same. • Bacteria, some plants and algae, and primitive animals (worms sponges and hydra)

Homeostasis is the maintenance of a stable level of internal conditions. • All living things have mechanisms that regulate their bodies so things stay balanced. • For example body temperature, water content, glucose levels etc. stay constant even though the environmental conditions change.

Living organisms increase in size and number of cells. • Cells get bigger and divide to create more cells. • The legs of a child grows longer as osteocytes divide to create new bone cells, enlarging the femur bones.

Response can be the result of a physical or chemical change in the environments. This change produces a purposeful response. • Externalstimuli • Deciduous trees respond to fewer hours of sunlight by dropping leaves. • Lizards body temperature drops when air cools, so it moves to a sunny rock for warmth. • Internalstimuli • Your body reacts to a disturbing dream with faster breathing and heart rate, possibly waking you up. • Your mouth may feel dry if you are dehydrated.

Excretion is the removal from the body of waste products which results from normal life processes. Waste products include:

Pasteurs experiment ( to investigate wether cells spontaneously generated or arose from pre e si siting cells ) in which broth was sterilized and then either exposed to air or protected from air born spores in a swan neck flask. Only teh broth exposed to air borne spores became contaminated with air support ‘omis cellula e cellular ‘. Basically Pasteur refuted Virchow.

Viruses are very small particles capable of infecting every type of living organism. They are parasitic and can only reproduce inside living cells.

the tobacco mosaic virus – this stops chloroplasts forming in tobacco plants and causes the tobacco leaves to become discoloured • the influenza virus – this causes flu • HIV (human immunodeficiency virus) – this causes AIDS

Metabolism Movement Reproduction Respiration Sensitivity Homeostasis Growth Response Excretion Nutrition

Eukaryotic cells are cells that contain a nucleus and organelles, and are enclosed by a plasma membrane.

Organisms that have eukaryotic cells include protozoa, fungi, plants and animals.

Contains genetic material ( DNA organized into chromosomes for inheritance ) of the organism and controls the cell’s activities.

The cytoplasm is a jelly like material that contains organelles such as mitochondria and chloroplasts. It is also the site of many chemical reaction controlled bye enzymes

Partially permeable membrane that forms the cell bounds and controls passage of substances in and out of cell

Semi rigid outer wall made of cellulose that supports the cel and prevents turgid cells from bursting

Is an organelle found in the cytoplasm, it contains chlorophyll.

Large fluid filled sac that swells, pushing the cytoplasm against teh wall, making teh cells turgid ( it helps keep teh cell firm). Cells shrink as the vacuole gets smaller

The cytoplasm is mainly made of water

Ova (egg cells) are some of the biggest in the human body.

Prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles.

• Prokaryotic cells are not divided up on the inside (like Eukaryotic Cells are) by membrane walls, but consist instead of a single open space. • prokaryotic cells are smaller • mitosis ( eu ) and binary fission (pro) • DNA in nucleus (eu) and DNA in a single molecule, found free in the cytoplasm (pro)