cells Flashcards
describe the cellulose cell wall
plant cell
- tough, non living, freely permeable layer made of cellulose surrounding the membrane
- provides strength to the cell
- prevents plant cells from bursting
- allows water and dissolved substances to pass through freely
permanent vacuole
plant cell
- contains cell sap
- found within the cytoplasm
- improves cells rigidity: watery sol. helps maintain shape + firmness of cell
- can store salts and sugars
- fluid filled space containing dissolved substances, surrounded by a membrane
chloroplasts
plant cell
- organelle containing chlorophyll
- inside cytoplasm of some plant cells
- where photosynthesis takes place, providing food for the plant
- converts light energy -> chemical energy stored
in molecular bonds of glucose
- plant uses the glucose molecules to create complex carbohydrates -- starch and cellulose -- and other nutrients that it needs to grow and reproduce.
- contains chlorophyll pigment (which makes it green) which harvests the light needed for photosynthesis
define eukaryotic
eukaryotic Eukaryotes are organisms made up of cells that possess a membrane-bound nucleus that holds genetic material as well as membrane-bound organelles. - cell membrane - cytoplasm - nucleus containing the DNA
nucleus
plant and animal
- controls cell division and development
- controls the activities of the cell
- inside cytoplasm
- contains DNA (in the form of chromosomes) coding for a particular protein needed to build new cells
- enclosed in a nuclear membrane
cytoplasm
plant and animal
- enclosed by cell membrane
- contains dissolved substances, particles and organelles
- liquid jelly-like substance in which chemical reactions occur
- contains enzymes (biological catalysts, ie. proteins that speed up the rate of reaction)
cell membrane
plant and animal
- partially permeable layer
- forms barrier around cytoplasm
- controls what enters and leaves the cell
- separates cell contents from the surroundings and keeps the contents from escaping
mitochondria
plant and animal
- where aerobic respiration reactions occur, providing energy (as ATP) for the cell
- each mitochondrion has double membrane, outer one controls entry and exit of materials
- inner has many folds on which some chemical reaction of aerobic respiration take place
ribosomes
plant and animal
- where protein synthesis occurs
- found on a structure called the rough endoplasmic reticulum
what structures are in bacterial cells
they are prokaryotic so they have
- cytoplasm
- cell membrane
- cell wall made of peptidogylcan
- singular strand of DNA (no nucleus, floats in the cytoplasm)
- plasmids- small rings of DNA
which small organelles are located in the cytoplasm (just list them)
include: mitochondria vesicles ribosomes rough endoplasmic reticulum
what do the cytoplasm of all cells contain
the cytoplasm of all cells contains vesicles and ribosomes on rough endoplasmic reticulum
rough endoplasmic reticulum
endoplasmic reticulum (ER) is a complex system of parallel membranes running throughout the cell
linked with both cell and nuclear membranes
contain fluid-filled spaces between the membrane -> allows materials to be transported throughout the cell
Rough ER is covered with ribosomes which make protein for the cell (main function of rough ER is to package + transport proteins)
cells that produce a lot of protein (eg. making digestives enzymes in alimentary canal -> large amounts of rough ER
small vesicles formed when small pieces of rough ER are pinched of at the ends
- proteins can be made and stored in rough ER, transported around cell in small vesicles
what do almost all cells, except prokaryotes have?
(almost) eukaryotic cells have mitochondria and rough ER
why would cells require large numbers of mitochondria
cells with high rates of metabolism require large numbers of mitochondria to provide sufficient energy
ribosomes
small organelles found in huge number in all cells
- 20 nm diameter in eukaryotic cells
- smaller in prokaryotic (free in cytoplasm, not attached to rough ER)
- function: synthesise proteins, eg those enzymes involved in respiration