Eukaryotic cells Flashcards
organelles def
structures within a cell
(sub- cellular structures)
cytoplasm
contains the cytosol, organelles and structural protein and cytoskeleton of a cell.
cytosol
aqueous component of the cytoplasm
Structures only in animal cells
centrioles and micro villi
structures only in plant cells
cellulose, cell wall, large permanent vacuoles , chloroplasts
Nucleus structure
- Surrounded by a double membrane (nucleus envelope)
- contains chromatin which consists of DNA wound around histone proteins. The chromatin condenses to from chromosomes, they are only visible when dividing.
Nucleus envelope structure
- surrounds nucleus
- contains pores
Nucleolus structure
- doesn’t contain a membrane
- contains RNA and proteins
Nucleus function
-directs protein synthesis
- controls metabolic activity of the cell.
Nucleus envelope function
- separates the contents of the nucleus from the rest of the cell
- protects the DNA from damage to cytoplasm
-Allows movement from in and out of the nucleus
Nucleolus function
responsible for producing ribosomes and where ribosomal RNA genes are transcribed
Mitochondria structure
-2-5 μm long
-double membrane. the inner membrane olds inwards to form cristae.
- centre of mitochondria filled with fluid called the matrix
mitochondria function
- Site of cellular aerobic respiration
-Self replicating, so more can be made if the cells energy needs increase - There’s many of them where many metabolic activity takes place eg, liver cells.
Ribosomes structure
- Small spherical organelles around 20 nm in diameter
- Made of ribosomal RNA
- Some attached to Rough endoplasmic reticulum or they may be floating free in the cytoplasm
- made from 2 separate sub units which passes through nuclear envelope then combine.
Ribosomes function
Used in protein synthesis
- bound ribosomes usually synthesise proteins that will be exported out of the cell
- ribosomes in cytoplasm usually synthesise proteins that will be used within the cell
Cell surface membrane structure
- made up of a phospholipid bilayer.
- partially permeable
- fragile
-boundary of all cells