2.1.1 Cell structure Flashcards
Magnification of light microscope?
1500x
Resolution of light microscope?
200nm
Magnification of transmission electron microscope (TEM)?
500,000x
Resolution of transmission electron microscope (TEM)?
0.5nm
What does a TEM show in a cell?
2D black and white images of the inside of a cell and smaller organelles
Magnification of a scanning electron microscope (SEM)?
100,000x
Resolution of a scanning electron microscope (SEM)?
3-10nm
What does a SEM show in a cell?
3D black and white images of the surface of the specimen
What does a laser scanning confocal microscope show in a cell?
3D coloured images of cells (due to fluorescent tag) which can be living and dead
mm —> μm —> nm
x1000 x1000
What is magnification?
How many times larger the image is than the actual size of the object being viewed
What is resolution?
The ability to see individual objects as separate entities
Magnification = __________ ÷ ____________
Image size ÷ Actual size
(ensure units are the same!)
What are prokaryotes?
Organisms which do NOT have membrane bound organelles
What are eukaryotes?
Organisms which DO have membrane bound organelles
Differences in DNA between prokaryotes and eukaryotes?
Prokaryote
- Circular
- Extra DNA: plasmids
Eukaryotes
- Linear
- Extra DNA: mitochondria and chloroplasts
Difference in ribosomes of prokaryotes and eukaryotes
Prokaryotes - smaller 70S
Eukaryotes - larger 80S
Difference in cell wall material of prokaryotes and eukaryotes?
Prokaryotes - made of peptidoglycan
Eukaryotes - made of cellulose in plants and chitin in fungi
What is the function of smooth endoplasmic reticulum?
Lipid and carbohydrate synthesis and storage
What does rough endoplasmic reticulum have on its surface?
Ribosomes
What is the function of rough endoplasmic reticulum?
Synthesis and transport of proteins
What does the nucleus contain?
- Nuclear membrane
- Nucleolus
- Chromatin
Why does the nuclear membrane have nuclear pores?
To allow RNA to move in and out of nucleus
Which protein forms chromatin?
Histones
What does the nucleolus do?
Produces ribosomes which create the DNA
What is the function of the Golgi apparatus?
Modifies and packages proteins into vesicles
What is the function of ribosomes?
Site of translation in protein synthesis
What is the structure of mitochondria?
- Double membrane structure
- Inner membrane highly folded to form cristae
- Matrix liquid contains enzymes for respiration
What is the function of mitochondria?
Site of cellular respiration
What is the function of lysosomes?
Vesicle containing hydrolytic enzymes which breaks down waste material in cell
What is the structure of chloroplasts?
- Double membrane structure
- Large SA due to stacks of thylakoids (granum)
- Thylakoids contain chlorophyll
- Stroma liquid
What is the function of chloroplasts?
Site of photosynthesis
What is the function of centrioles?
Assembly and organisation of spindle fibres during cell division
What is the function of flagella and cilia?
Movement
What is the function of plasma membrane?
Selectively permeable to control what goes in and out of the cell
What is the function of the cell wall?
Gives cell support and keeps it rigid
Order of organelles involved in protein synthesis?
Ribosomes -> rough endoplasmic reticulum -> vesicles -> Golgi apparatus -> vesicles -> cell surface membrane
(some vesicles form lysosomes which do not leave cell)
By what process do proteins leave the cell?
Exocytosis
What are the 3 components of cytoskeleton?
- Microfilaments
- Microtubules
- Intermediate fibres
What is the function of microfilaments?
Controls cell movements and cell contraction during cytokinesis
What is the function of microtubules?
Determine shape of the cell and allow for transport of organelles and materials around the cell
What is the function of intermediate fibres?
Give strength to cells and helps to maintain their shape
Which domain of life has the 9+2 formation of microtubules?
Eukaryotes
What can prevent microtubules from functioning? Why?
Respiratory enzymes as microtubules need ATP to function
