cell structure Flashcards
what are the organelles found in an animal cells and plant cells- eukaryotic
- cell surface membrane
- nucleus
-mitochondria - ribosome
-smooth endoplasmic reticulum
-rough endoplasmic reticulum
-golgi apparatus and golgi vesicles
-lysosome
-cytoplasm
-nuclelous
-nuclear envelope
what are the additional organelles in plant cell
- permanent vacuole
- cell wall
- chloroplast
what is the function of the nucleus
- site of DNA replication and transcription [ making mRNA]
-holds genetic information which codesfor polypeptides
what is the structure of the nucleus
- contains chromosome- associated histone proteins and linear DNA
- the nuclear envelope is a double membrane and has nuclear pores to control exchange between the nucleus and cytoplasm
-nucleolus is a small sphere inside which is the site of rRNA production and makes ribosomes
-nucleoplasm
what is the function of the rough endoplasmic reticulum
● Ribosomes on surface synthesise proteins
● Proteins processed / folded / transported inside rER
● Proteins packaged into vesicles for transport to Golgi apparatus
what is the structure of the rough endoplasmic reticulum
- a system of folded membrane called cisternae which have ribosomes on it
what is the function of the smooth endoplasmic reticulum
- synthesis and processes lipids
what is the structure of the smooth endoplasmic reticulum
stacks of flattened folded membrane called cisternae with no ribosomes
what is the function of the Golgi apparatus
● Modifies protein, eg. adds carbohydrates to produce glycoproteins
● Modifies lipids, eg. adds carbohydrates to make glycolipids
● Packages proteins / lipids into Golgi vesicles
Golgi vesicles transport proteins and lipids to their required destination
● Produces lysosomes
what is the structure of the golgi apparatus
Stacks of flatterned membranes called cisternae
- secretary vesicles pinch off the cisternae
what is the function of lysosomes
contains hydrolytic enzymes called lysozymes which are used to digest and hydrolyse invading cells or digest worn out organelles [ exocytosis]
what is the structure of lysosomes
round organelle with a membrane
- bags of diff digestive enzymes
what is the function of the mitochondria
the site of aerobic respiration
- site of ATP production
- DNA to code for respiration
what is the structure of mitochondria
- double membrane which has an inner membrane called the cristae
-fluid centre called matrix where aerobic respiration takes place - loop of DNA
what is the function of ribosomes
- site of protein synthesis
what is the structure of ribosomes
- made up of proteins and RNA
-80s in eukaryotic cells [ 25NM]
-70s in prokaryotic
what is the function of cell surface membrane
● Selectively permeable → enables control of passage of substances in / out of cell
● receptors / antigens on surface → allow cell recognition / signalling
what is the structure of the cell surface membrane
- thin phospholipid bilayer surrounds the cell
what is the function of the permanent vacuole
contains cell sap
makes cell turgid for support
what is the function of chloroplast
site of photosynthesis- absorbs light
Produces organic substances
what is the structure of the chloroplast
- surrounded by a double membrane
-Stroma contains thylakoid membrane contains ribosomes and circular DNA
Thylakoid membrane are stacked up to form grana
Grana is linked with lamellae
what are the organelles in a prokaryotic cell
-cytoplasm
-ribosomes
-capsule
-cell wall
-cell surface membrane
-genetic DNA loop
-flagellum
-plasmids
how do prokaryotic cells differ from eukaryotic cells
-cytoplasm that lacks membrane-bound organelles
-smaller ribosomes
no nucleus- a single circular DNA molecule that is free in cytoplasm and is not associated with histone proteins
- plasmid
No membrane bound organelles
in addition many prokaryotic ells have
one or more plasmids
- a capsule surrounding cell
-one or more fagella
what is a virus
theyre acellular and non-living
what is the structure of a virus
genetic material
protein capsid
attachment proteins
true or false prokaryotic cells are much smaller than eukaryotic cells
true
in complex multicellular organisms,
what happens
eukaryotic cells become specialised for specific functions
how are specialised cells organised
tissues, tissues into organs, organs into systems
Why is it difficult to destroy a virus
They replicate inside cells which may harm host cells
Describe the structure and function of cell wall
-made of carbohydrates and cellulose
-supports and strengthens the cell
Describe the structure of the cell wall in plants, algae and fungi
● Composed mainly of cellulose (a polysaccharide) in plants / algae
● Composed of chitin in fungi
what is a tissue
Group of specialised cells with a similar structure working together to perform a specific function
what is an organ
A collection of tissues performing certain functions
what is an organ system
Group of organs working together to perform specific functions
Explain why viruses are described as acellular and non-living
● Acellular - not made of cells, no cell membrane / cytoplasm / organelles
● Non-living - have no metabolism, cannot independently respire / replicate
