cell structure 2 because i suck Flashcards
In relation to cm give mm, um and nm. [3]
10mm, 10000um, 10000000nm
equation for calculating actual size
a=i/m
Define magnification
The number of times an image is larger than the original
Define resolution
The smallest distance between two points where the two points can still be distinguished
What are the two types of microscope? [2]
Scanning and Transmission
Describe the structure of the nucleus [4]
- Surrounded by nuclear envelope
- Nuclear pores allow more molecules movement
- genetic material is found within, usually as chromatin
- the nucleolus is a region within that synthethises ribosomes
What are the roles of the nucleus? [3]
- To store the genetic material (DNA) of the cell
- To synthesise ribosomes
- Regulate the production of messenger RNA for protein synthesis
What are the functions of the cell surface membrane? [3]
- Encloses the cell to form the boundary between the cytoplasm and the outside environment.
- The control the movement of substances in and out of the cell, as it’s secretively permeable.
- Contains proteins and important molecules for cell signalling and recognition.
How does the structure of the RER relate to it’s function? [2]
- Contains ribosomes on it’s surface for synthesis of proteins
- The RER membranes spread extensively throughout the cell for the transport of proteins
How is the structure of the RER different to the SER?
The smooth endoplasmic reticulum does not have ribosomes on it’s surface.
What is the function of the smooth endoplasmic reticulum?
Synthesises and transports lipids
Describe the structure of mitochondria [4]
- Oval shaped
- Double membrane bound, inner membrane folded into cristae
- contain jelly like fluid called the matrix
- contain circular DNA and 70s ribosomes
What important process occurs at the mitochondria?
Aerobic respiration, which produces ATP. This is used for energy requiring processes
State the function of the golgi body [2]
- Modification and packaging of proteins and lipids for exocytosis or distribution within the cell
- Produces lysosomes
What are lysosomes?
Vesicles from the golgi body that contain digestive enzymes (protease, lipase etc)
List the functions of lysosomes [3]
- Hydrolyse ingested pathogens in phagocytes
- They digest old, worn out organelles in the cells
- Break down cells after cell death
What are the two types ribosome [2]
70s and 80s ribosomes
Where are the two types of ribosomes found? [4]
- 80s ribosomes are found in Eukaryotic cells - in the cytoplasm and on the RER
- 70s ribosomes are found in prokaryotic cells - chloroplasts and mitochondria
Describe the structure of ribosomes [2]
- Contain two subunits
- Each is made up of a ribosomal RNA molecule and a protein
What is the functions of ribosomes?
Protein synthesis
State the function of centrioles [3]
- formation of the spindle during nuclear division
- replicate during cell division
- organise microtubules during mitosis
State the functions of microtubules [2]
- Make up the cytoskeleton
- to give structure and allow transport with the cell
What are microvilli?
Small protrusions of the cell membrane
How do microvilli aid exchange of substances in cells?
They increase the surface area of a cell to increase the efficiency of exchange
