biology 1.4 organelles Flashcards
(22 cards)
where are ribosomes found
both prokaryotic and eukaryotic cells
describe ribosomes
they lack a membrane and are extremely small about 0.03 micrometers in diameter
what is the function of a ribosome
the function of a ribosome is to convert a code from the nucleus (mRNA) into a functional protein. protein synthesis.
where in the cell are ribosomes found
they are found free-floating in the cytoplasm or in an eukaryotic cell they are attached to the membrane of the endoplasmic reticulum
why are proteins needed
- repair
- growth
- maintaining cell structure
- hormones
- transport oxygen (haemoglobin’s)
- digestive enzymes
what are proteins made of
amino acids
what is the nucleus
the nucleus is a distinct spherical structure that is enclosed within a double membrane known as the nuclear envelope/nuclear membrane.
what do NPCs do in an animal cell
control the exchange of materials between the nucleus and the cytoplasm
how is a functional protein made
the polypeptide chain of amino acids assembled at the ribosomes is folded into a 3d shape to make a functional protein
what are the functions of the nucleus
- control of DNA replication during cell division
- repair of genetic material
- control of the metabolic actives of a cell
what is the nucleolus
the nucleolus is composed of RNA and its function is to produce the RNA that forms part of the ribosomes.
what is the mitochondria
it is an organelle that is the major site of ATP production
what is the function of the mitochondria
to convert chemical energy (glucose) into a useable form (ATP)
what produces ATP
plant and animal cells produce ATP in the process of cellular respiration
how can mitochondria be seen
with an electron microscope
how many mitochondria is in each cell
the number of mitochondria in different cell types varies, the more active the cell is the greater number of mitochondria in that cell
what is the endoplasmic reticulum
it is an interconnected system of membrane-enclosed flattened channels
what is the difference between the rough ER and the smooth ER
rough ER has ribosomes attached to the outer surface whereas the smooth ER does not have any attached ribosomes. the rough and smooth ER are seperate networks of chandelles are are not physically connected
what is the job of the rough and smooth ER
they are both involved in transporting different materials within cells
what jobs does the rough ER specifically do
it is involved in transporting some of the proteins to various sites within a cell. this transportation is internal and the rough ER also modifies proteins
what does the smooth ER specifically do
it is involved in the manufacture of substances, detoxifying harmful products and the storage and release of substances. lipid synthesis and storage is also done by the smooth ER
what is the difference between the nucleus and nucleolus
nucleus - enclosed in membrane, contains dna, controls gene expression
nucleolus - not enclosed in membrane, contains ribosomal rna , produces rna
