Module 2 Section 1 - Cell Ultrastructure Flashcards
What are the 3 structural components of a cytoskeleton
1) Microfilaments
2) Microtubules
3) Intermediate Fibres
What are the functions of a Cytoskeleton
- To provide mechanical strength
- Aiding transport with cells
- Enabling Cell movement
what are microfilaments made of
the protein Actin
what is the microfilament of the cytoskeleton responsible for
movement of the cell and cytoplasm during cytokinesis
what are microtubules made of
the protein tubulin
microtubules can also act as…
tracks for organelles moving around the cell
intermediate fibres give…..
strength to cells and help maintain integrity
what is the structure of the nucleus
- Double nuclear envelope
- nuclear pores
- nucleolus
- chromatin
what is the double nuclear envelope
a double membrane which separates the nucleus and prevents damage. protects the DNA
what are nuclear pores
allows molecules to enter(e.g. nucleotides for DNA replication) and leave the cell e.g. mRNA leaves the cell.
what is the nucleolus
site of ribosome production, composed of RNA and proteins
what is chromatin
the DNA (with associated histone proteins). contains the genetic code which controls the activity of the cell
what is the function of the nucleus
-controls all the activity of the cell
-where genetic code (DNA) of the cell is stored, replicated, and copied into RNA
- the nucleus is attached to the rough ER (endoplasmic reticulum) so the mRNA can esily get to ribosomes
what is the structure of rough endoplasmic reticulum (rough ER)
-stacks of membrane bound sacs which form sheets called cisternae
-it is also attached to nucleus and covered with ribosomes
what is the function of the rough ER
site of protein synthesis
what is the structure of the smooth ER
similar to rough ER but it lacks ribosomes - is a system of interconnected tubules
what is the function of the smooth ER
responsible for carbohydrate & lipid synthesis as well as storage
what is the structure of ribosomes
- a 2 subunit organelle
- made from RNA and protein
- not membrane bound
- about 22nm in diameter
- found free floating in the cytoplasm or attached to the rough ER
what is the function of ribosomes
- this is where protein is made
- they assemble amino acids into proteins in chains using mRNA
what is the structure of the mitochrondria
-oval shaped
-surrounded by 2 membranes
- inner membrane called cristae which increases the surface area
- the solution inside is called matrix which contains enzymes for respiration
why is mitochrondrial dna important
it enables mitochrondrion to reproduce and create enzymes
what is the function of mitochrondria
- site of aerobic respiration which releases atp (energy carrier in cells)
what is the strucutre of the golgi apparatus
- stacks of flattened, membrane bound sacs (cisternae)
- these are contiously formed from the ER at one end and budding off as golgi vesicles at the other
what is the function of the golgi appartus
- allows internal transport
- recieves proteins from the rough ER
- modifies and processes molecules (e.g. lipids and proteins) and packages them into vesicles
- these may be secretory vesicles (leaving the cell) or lysosomes (stay in the cell)
- make lysosomes
- lipid synthesis
what is the structure of lysosomes
they are spherical sacs surrounded by a membrane
what is the function of the lysosomes
- they contain powerful digestive enzymes called lysozymes their role is to break down worn out components of the cell or digest invading cells
what is the structure of the centrioles
- a component of the cytoskeleton, composed of many microtubules
- small hollow cylinders that occur in pairs next to the nucleus in animal cells
- each centriole contains a ring of 9 microtubules
what is the function of centrioles
makes a copy of itself during cell division and then helps to form the spindle in cell division
what is the strucutre of the cilia
- hair-like extensions that protrude from some animal cell types
- in cross section they have an outer membrane and a ring of nine pairs of protein microtubules inside with 2 microtubules in the middle
- known as a 9+2 arrangement which allows movement
what is the function of the cilia
- sensory function (e.g. nose), beat creating a current to move fluid/muscous/objects
- for locomotion
what is the structure of the flagella
- similar to cilia but longer
-they protrude from the cell surface and are surrounded by the plasma membrane - like cilia they have a 9+2 arrangement
what is the function of the flagella
-enables cell mobility
-the microtubules contract to make the flagellum
-propel the cell forward
what is the structure of the chloroplast (plant cells only)
double membrane which encloses the stroma
stroma contains: strach grains, lipid stores, DNA, RNA, Ribosomes
series of membrane-bound flattened sacs called thylakoids in the stroma.
stacked thylakoids are called grana which is connected by lamellae
the grana contain chlorophyll
what is the function of the chloroplast - plant cell only
photosynthesis reactions
what is the structure of the cell surface membrane
a phospholipid bilayer (phosphorus and lipid)
composed of proteins and lipids
where is the cell surface membrane found
on the surface of animal cells
inside the cell wall of plant and prokaryotic cells
what is the function of the cell surface membrane
it regulates the movement of substances in and out of the cell
contains receptor molecules that allow it to respond to chemical like hormones
what is the structure of the cellulose cell wall
composed of b-cellulose microfibrils - complex carbohydrate
cell wall fully permeable to substance
thin layer called middle lamella marks the boundary between adjacent cell walls and ‘cements’ adjacent cells together
what is the function of the cellulose cell wall
gives plant mechanical strength
gives plant cell support and it’s shape
contents of plant cell can ‘push’ against the cell wall (turgid cell). this gives the cell good support
what is the structure of large permanent vacuole
single membrane bound - called tonoplast
contain cell sap
selectively permeable barrier
what is the function of the large permanent vacuole
stroes cell sap
support herbaceous plants by make cells turgis
hepls maintain shape and mains turgor pressure
sugar and amino acids act as temporary food stroe
