Organelle structure and function Flashcards
Define ultrastructure
internal structure which suits the cell to its function
Define Eukaryotic
distinct nucleus
membrane bound organelles
What is the function of the nucleus?
Site of DNA replication and transcription
Contains genetic code
controls the cells activity
What is the size of the nucleus?
10-20 um
List and describe the 5 parts of the nucleus and their function
nuclear envelope= double membrane continuous with the ER. Controls the entry/exit of materials and contains the reactions talking place
Nuclear pores= allows large molecules(mRNA) to exit the nucleus, typically 3000 per nucleus, 40-100nm diameter
Nuclear pore= granular, jelly like substance that is the bulk of the nucleus
Chromosomes= protein bound linear DNA
Nucleolus= manufactures ribosomal RNA and ribosomes
What is the function of the mitochondria?
produces ATP
site of aerobic respiration
What is the size of the mitochondria?
1-10um
Describe the three parts of the mitochondria
Double membrane= controls entry and exit of materials
Cristae= extension of the inner membrane which provides a large SA for the attachment of enzymes and proteins
Matrix= rest of mitochondria/ contains protein, lipid, ribosomes, DNA (controls production of own proteins), enzymes involved in respiration
Function of ribosomes
site of protein synethesis
what are the two types of ribosomes
*80S = eukaryotes, 25nm in diameter
70S= Prokaryotic, mitochondria , chloroplasts
Chloroplast function and size
carry out photosynthesis
2-10um long and 1um in diameter
Name the three main features of the chloroplasts
Chloroplast envelope= double membrane that controls entry/exit
Grana= stacks of up to 100 thylakoids( contain chlorophyll)/ where the first stage of photosynthesis occurs
Stroma= fluid-filled matrix where the second stage of p. occurs
How is the chloroplast adapted to their function?
grana membrane= large SA for the attachment of enzymes/ electron carriers/chlorophyll. These chemicals are attached to the membrane in a highly ordered fashion
fluid of the stroma possess all the enzymes needed to make the sugars in the 2nd stage of photosynthesis
contains both DNA and ribosomes so they can easily manufacture some proteins needed for photosynthesis
Describe the structure of the cell wall and how that links to their function
consist of microfibrils of polysaccharide cellulose, embedded in a matrix. The cellulose microfibrils have considerable strength.
Describe the features of the cell wall
consist of polysaccharides eg cellulose
thin layer called middle lamella which marks the boundary between adjacent cell walls and cements them together.
Explain the functions of the cell wall
to provide mechanical strength
allow water to pass along it so contributes to the movement of water through the plant.
What are algae and fungi cell walls made up of?
Algae= cellulose or glycoproteins or a mix
fungi=mix of chitin, glycan and glycoproteins
Define vacuole
a fluid-filled sac bounded by a single membrane
Describe vacuole structure
single membrane around vacuole = tonoplast
contains solution of mineral salts, sugars, amino acid , wastes, sometimes anthocyanins
Name the functions of the vacuole
support herbaceous plants/ parts of wood plants by making cells turgid
sugars and amino acids act as a temporary food store
pigment may colour petals to attract pollinating insects
Describe the Endoplasmic reticulum structure
3d system of sheet like membranes in the cytoplasm continuous with the outer nucleus membrane. The membrane encloses a network of tubules and cisternae
Name the two types of Endoplasmic reticulum and what is their difference?
Rough and smooth
Rough has ribosomes on its outer surface, smooth does not and is often more tubular in appearance
Describe the function of the RER
provide large SA for (glyco) protein synthesis
Describe the function of the SER
synthesis,store and transport lipids and carbohydrates
