IB Bio - Cells

not finished yet

unicellular organisms

single celled and carry out life functions independently

multicellular organisms

have specialized cells to carry out specific functions

three principles of cell theory

1. all living things are made of cells

2. cells are the smallest functional unit of life

3. cells can only be formed by division of pre-existing cells

how eukaryotes divide

mitosis and meiosis

how prokaryotes divide

binary fission

growth

the increase in mass and volume of an organism over time

metabolism

the sum of all chemical activity taking place within an organism to maintain life

movement

allows organisms to find food and shelter, avoid predation, and find mates in order to reproduce

response to stimuli

an organism’s reactions to environmental changes

reproduction

the process by which living organisms produce new members of their species

nutrition

chemical ingredients needed for growth, reproduction, and other processes

autotrophic

organism’s ability to produce their own food

excretion

process of removing built up waste from metabolism

homeostasis

an organism’s ability to maintain its internal environment despite changes in its external environment

contractile vacuole

used to maintain osmolarity (solute concentration) in the cytoplasm

cytoplasm

watery solution that contains dissolved substances such as proteins and enzymes

ribosomes

responsible for synthesis of polypeptides by translation

DNA

contains information required by the cell to carry out all processes (eg. growth, repair, and replication)

plasma membrane

separates the cell from its exterior environment. composed of a phospholipid bilayer and is semipermeable

advantage of a cell having no nuclei

maximizes the space they have in order to carry out their transportation responsibility

magnification formula

magnification = measured length / scale bar length

actual size

actual size = measured length / magnification

fluoresence

absorbance of light and re-emission at a longer wavelength

how do prokaryotic cell walls differ from eukaryotic cell walls

contains peptidoglycan

size of prokaryotic ribosomes

70S

size of eukaryotic ribosomes

80S

nucleus

holds cell’s chromosomes and has a double membrane with pores

what is eukaryotic DNA associated with

proteins — histones

plastids

a family of organelles with two outer membranes and internal membrane sacs — plants only

cell wall

a rigid layer outside the plasma membrane - fungi and plants

vacuole

a flexible fluid-filled compartment surrounded by a single membrane

centrioles

cylindrical organelles that organize assembly of structures composed of microtubules

undulipodia

cilia and flagella used to generate movement of a cell or fluid adjacent to a cell

organelle

structure that is adapted to perform one or more vital functions in a cell

exocytosis

moving out of the cell membrane

endocytosis

moving into the cell membrane