cells

prokaryote

simplest form of cell; bacteria; genetic material lacks a nuclear membrane and membrane bound organelles in general

eukaryotic cells

fungi, plants, animals, protists; have a nuclear membrane and membrane bound organelles.

cell wall (p)

outermost layer of the cell; made of murin;gives the cell shape and provides protection

plasma membrane/cell membrane (p)

made of a phospholipid bi-layer which makes it flexible; seperates the inner environment (cytoplasm) from the outer environment; semi permeable; allows cell to cell communication.

mesosomes (p)

infoldings of the cell membrane; site where energy may be released.

cytoplasm(p)

water like base inside the cell; contains all chemicals required for metabolic reactions; contains all cell contents; site wehre most chemical reactions take place.

flagellum (p)

thread like structure which rotates; allows locomotion.

naked nuclei acid/bacterial chromosome (p)

a large coiled circular DNA molecule; not enclosed by a membrane; found floating freely in the cytoplasm (the nucleoid); controls all cell activity including cell division; also contains genetic code required for protein synthesis; proteins needed for cell growth and functioning in general.

plasmid (p)

a circular ring of DNA, seperate from the NAKED NUCLEIC ACID; enhances chances of survival (contains codes against medications etc.) ; used for bacterial cells to exchange DNA.

70s Ribosomes (p)

Small structures; not membrane bound; composed of RNA and proteins; Involved in protein synthesis.

plasma membrane/cell membrane

Thin, Flexible, Partially permeable barrier around the cytoplasm. Separates the cytoplasm from the exterior environment and controls what movies in and out of the cell allowing cell communication.

cytoplasm

water like liquid found inside the cell.

contains all chemicals needed for cell to function and is the site where most chemical reactions take place.

cytoskeleton

network of fibres attached to the plasma membrane extending all throughout the cell.

acts like the cells skeleton, giving shape and supporting the cell. it positions and moves the organelles.

nucleus

the center which controls cell activities including growth and division. makes ribosomes.

what is the largest organelle and what does it consist of?

nucleus:

nuclear envelope: double membrane with nuclear pores

chromatin: strands of DNA associated with proteins.

nucleolus: a round dark structure within the nucleus

80s ribosomes

smallest most numerous organelle; divided into two sections made out of proteins and RNA; either found roaming freely in the cytoplasm or attached the endoplasmic reticulum

make proteins

centrioles

barrel shaped structures situated at rigth angles from eachother.

involved in cell division.

mitochondria

oval shaped structures surrounded by two membranes (inner membrane has folds called cristae)

release energy from food making it available to the cell.

rough endoplasmic reticulum

system of interconnected membrane bound channels studded with robosomes and continuous with the outer memberane of the nuclear envelope.

modifies and transports proteins made by the ribosomes.

smooth endoplasmic reticulum

system on interconnected membrane mound channels

manufactures and transports materials; mainly lipids

golgi apparatus

stack of flattened membrane bound sacs from the endoplasmic reticulum.

parts of the endoplasmic reticulum containing materials for transport to other organelles or for exports from the cell fuse with one side of the goli while the other side small vesicles bud off

modifies, packages and transports materials in vesicles to other membrane bound organelles or to the plasma membrane with which they fuse and release their contents.

lysosomes

small membrane bound vesicles formed by the golgi apparatus containing enzymes which breakdown substances.

breakdown unwanted and harmful substances, old organelles or even the entire cell so materials can be recycled.

cillia and flagella

flexible extensions of the cytoskeleton; surrounded by the cell membrane present only in some cells.

flagella tend to be longer than the cell and only a few in number

cillia tend to be much shorter and more numerous

locomotion of the cell through fluids; creation of currents in fluids

cell wall

only found in plant cells

thick, rigid and fully permeable; made of cellulose fibres; outside the plasma membrane

protects; gives shape; and supports the cell.

large central vacuole

found only in plant cells

membrane bound sac filled with cell sap; surrounded by a thin layer of cytoplasm.

keeps cell turgin and stores substances such as waste products, food, and pigments.

chloroplasts

only found in plant cells

similar to mitochondira these are surrounded by membranes and have their own circular DNA and 70s ribosomes. 3rd system of membranes which run through a semi fluid substance called stroma. this system consists of many flattened filled sacs called thylakoids which have chlorophyll attached to their surface. thylakoids form stacks called grana

site of photosynthesis