chap 2: how do cells function? Flashcards
cell theory (3 things)
- All living things are made of cells
- cells are the simplest unit of a living thing
- all cells come from previously existing cells
main things about prokaryotes
no membrane bound organelles; only ribosomes. contains DNA and plasmids. much smaller than eukaryotes
similarities and differences between prokaryotic and eukaryotic cells
similarities
- both contain ribosome, DNA
- cell wall can be found in both
- ATP is a source of energy
- both have a cell membrane
differences
- eukaryotes have membrane bound organelles while prokaryotes don’t
- eukaryotes are usually multicellular organism
- eukaryotes are larger in size
organelle
specialised subunit of a cell. can be either membrane bound or non-membrane bound.
what is the nucleus?
it is the largest organelle in a cell. it holds chromatins with consist of DNA and proteins to make chromosomes.
key features of the nucleus (2 things)
holds nearly all of the cells genetic material to make proteins (chromatin)
nuclear envelope
- nuclear pores that allow the exchange of substances in/out of the nucleus.
nucleolus
- makes ribosomal RNA which is used to make and assemble ribosomes
nucleous
- makes ribosomal RNA which is used to make ribosomes
what is the Golgi apparatus?
a flattened stack of single membrane-bound sacs called cisternae. the membrane surrounds an area of fluid called lumen which is where complex molecules are stored and changed
function of golgi apparatus
receives proteins from the the rough endoplasmic reticulum and modifies them by adding sugar to make glycoprotein or add lipids to them, making lipoproteins. It helps fold the protein into a 3D shape and it packages it into vesicles so they can be transported.
what is a vesicle?
a small fluid filled double membrane bound organelle in the cytoplasm.
function of vesicle
helps transport things in/out of organelles/cells
what is a lysosome?
specialised vesicle that contain digestive enzymes.
function of lysosome
to break down materials
what is the rough endoplasmic reticulum (rough ER)?
series of single membrane bound sacs that are flattened called cisternae. There are ribosomes around the surface area.
function of rough endoplasmic reticulum
the proteins that are produced by the ribosomes are folded into the correct shape while being moved through the cinsternae.
what is the smooth endoplasmic reticulum?
it has the same structure as the rough ER but no ribosomes, and is involved with making lipids that a cell needs, such as cholesterol, phospholipids and steroid hormones.
what is the mitochondria/mitochondrion?
(powerhouse of the cell) it is an energy generating organelle which is surrounded by 2 membranes.
function of the mitochondria
it creates ATP through cellular respiration, which is supplied to nearly all the parts of the cell.
what is a centrioles / centrosome?
only found in animal cells, each centrosome has 2 centrioles which organise spindle fibres during mitosis and meiosis
what is chloroplast?
only found in plant cells, it is a double membrane bound organelle. flattened, fluid filled sac, which is the site of photosynthesis. it creates glucose
what is a vacuole?
membrane bound sac that is for water and solute storage which maintains plant cell structure
what is the plasma membrane?
a semipermeable membrane that surrounds all cells. it is made of phospholipids.
what is a cell wall?
the cell wall is only found in plant cells that is a sturdy border around the plasma membrane which provides strength and structure.
what is a vesicle?
a small membrane bound sac that transport substances in/out of cell. it also stores substances in a cell
what is the cytoskeleton?
a larger network of protein filament which maintain the shape and transporting of vesicles around the cell.
