Cell Structure Flashcards
(75 cards)
1
Q
What is the function of the Vacuole?
A
- To keep the cell turgid
- Membrane bound sac to store organic and inorganic substances as well as waste
2
Q
What are the 4 main features of the vacuole?
A
- Tonoplast
- High hydrostatic pressure
- Coloured pigments
- Large volume
3
Q
What is the function of the tonoplast within a vacuole?
A
- Control entry/ exit of substances
- Compartmentalisation
4
Q
What is the function of having a high hydrostatic pressure within a vacuole?
A
- For turgidity
5
Q
What is the function of coloured pigments within a vacuole?
A
- To attract insects for pollination
6
Q
What is the function of a large area within a vacuole?
A
- To push the chloroplasts to the outer edges for maximised CO2 and light absorption
7
Q
What is the function of the cellulose cell wall?
A
- Strength and rigidity
- Fully permeable to solutes
8
Q
What are the 4 main features of a cellulose cell wall?
A
- Strong composite structure of cellulose microfibrils within a pectin matrix
- Permeable network of cellulose microfibrils
- Middle lamella made of pectin
- Pits and Plasmodesmata
9
Q
What is the function of a strong composite structure of cellulose microfibrils within a pectin matrix in the cell wall?
A
- To give the cell strength when it is turgid
10
Q
What is the function of a permeable network of cellulose microfibrils in the cell wall?
A
- Allow substances to easily pass through
11
Q
What is the function of a middle lamella made of pectin within the cell wall?
A
- To hold cells together
12
Q
What is the function of the pits and plasmodesmata in a cell wall?
A
- To allow substances to move easily from cell to cell
13
Q
What is the function of an amyloplast?
A
- To store glucose as an insoluble carbohydrate so it can be hydrolysed back to glucose when required
14
Q
What are the 3 main features of an amyloplast?
A
- Insoluble starch
- Easy to hydrolyse
- Compact structure
15
Q
What are the 2 reasons starch is insoluble within an amyloplast?
A
- So it doesn’t affect osmosis
- So a store is able to be maintained without leaving the cell
16
Q
Why is the insoluble starch easy to hydrolyse in an amyloplast?
A
- So it can be converted to glucose when needed for reactions like cell wall synthesis, respiration.
17
Q
Why does the amyloplast have a compact structure?
A
- So lots of carbohydrates/ glucose is able to be stored in a small space
18
Q
What is the function of a chloroplast?
A
- To absorb light in photosynthesis for glucose
19
Q
What are the 4 main features of a chloroplast?
A
- Contain enzymes in the stroma
- Contain ribosomes and DNA in the stroma
- Stacks of thylakoid membranes in the grana
- Double membrane
20
Q
What is the function of having DNA and ribosomes in the stroma of a choroplast?
A
- So it can perform protein synthesis independent from the rest of the cell
21
Q
What is the function of having enzymes within the stroma of a chloroplast?
A
- To catalyse the many photosynthesis reactions
22
Q
What is the function of the stacks of thylakoid membranes in the grana of a chloroplast?
A
- Large SA for chloroplasts and therefore photosynthesis
23
Q
Why does a chloroplast have a double membrane?
A
- Compartmentalisation
24
Q
What is the function of the mitochondria?
A
- Aerobic respiration
- Release energy from glucose for ATP
25
What are the 4 main features of the mitochondria?
- Cristae
- Matrix
- DNA and ribosomes
- Double membrane
26
What is the function of a cristae within the mitochondrion?
- Large SA with enzymes for ATP production
27
What is the function of the matrix within the mitochondrion?
- Contain enzymes
- Contain the mitochondria's DNA
28
What is the function of the DNA and ribosomes within a mitochondrion?
- To perform protein synthesis independent from the rest of the cell
29
Why does the mitochondria have a double membrane?
- Control the entry/ exit of substances
- Compartmentalisation
30
What is the function of the Golgi apparatus?
- To modify, tag and package polypeptides into new proteins
31
What are the 4 main features of the Golgi apparatus?
- Membrane bound cavities
- Enzymes within the cavities
- Form Secretory vesicles
- Lysosomes
32
What is the function of the membrane bound cavities in the Golgi?
- Compartmentalisation
33
What is the function of the enzymes within the cavities in the Golgi?
- To catalyse the reactions
34
What is the function of the secretory vesicles in the Golgi?
- To transport newly formed proteins out of the cell
35
What is the function of the lysosomes released by the Golgi?
- To break down and destroy old worn out cells with lysozymes (hydrolytic enzymes)
36
What is the function of the smooth endoplasmic reticulum?
- To synthesise, store and transport lipids
37
What is the function of the rough endoplasmic reticulum?
- Protein synthesis
38
What are the 4 main features of the RER?
- Cisternae
- Large SA
- Form vesicles
- Ribosomes
39
What is the function of the cisternae in the RER?
- Compartmentalisation
40
What is the function of the large SA within the RER?
- Millions of attachment points for ribosomes for protein synthesis
41
What is the function of the ribosomes in the RER?
- Protein synthesis
42
What is the function of the vesicles formed by the RER?
- To transport polypeptides to the Golgi apparatus
43
What is the function of the nucleus?
- To produce ribosomes
- To store genetic information
- To release polypeptides for modification at the Golgi
44
What are the 5 main features of the nucleus?
- Nuclear pores
- Nucleolus
- Nuclear envelope
- Chromatin
- Nucleoplasm
45
What is the function of nuclear pores in the nucleus?
- Control entry/ exit of substances
46
What is the function of the nucleolus in the nucleus?
- Contain the genes that code for ribosomes
47
What is the function of the nuclear envelope in the nucleus?
- Compartmentalisation
- Control entry/ exit of substances
48
What is the function of the chromatin in the nucleus?
- Allow the genes to be read
49
What is the function of the nucleoplasm in the nucleus?
- Site of reactions
50
What are the size of ribosomes in eukaryotes?
- 80S
51
What are the size of ribosomes in prokaryotes?
- 70S
52
What are the features/ functions of fungal cells?
- Contain most of the organelles found in plant cells
- Contain chitin in the cell wall rather than cellulose
- Don't contain chloroplasts
53
What are the features/ functions of algal cells?
- Contain the same organelles as plant cells
- Chloroplasts are a different shape
54
What are the differences between eukaryotic cells and prokaryotic cells?
- Eukaryotic cells contain a nucleus, prokaryotic don't.
- Eukaryotic ribosomes are larger than prokaryotic ribosomes.
- Eukaryotic cells are larger than prokaryotic cells.
- Cell wall is made of murein in prokaryotic cells, but cellulose or chitin in eukaryotic cells.
55
What are some features in prokaryotic cells that are not found in eukaryotic cells?
- Capsule
- Flagellum
- Pili
56
What is the function of the capsule in prokaryotic cells?
- Protects the cell from attacks from antibiotics or white blood cells
57
What is the function of the flagellum in prokaryotic cells?
- To propel the cell through the environment
58
What is the function of the pili in prokaryotic cells?
- To attach the cell onto other surfaces or cells
59
What are the features of a virus?
- Genetic material
- Glycoproteins
- Capsid
- Envelope
- Enzymes
60
What type of genetic material is found in a virus?
- DNA or RNA, both single or double stranded
61
What is the function of the capsid in a virus?
- To protect the genetic material
62
What is the function of the glycoproteins in a virus?
- To help the virus bind to host cells
63
What is the function of the enzymes that are sometimes carried in a virus?
- To convert RNA into DNA
64
What is the maximum resolution and magnification of a light microscope?
Resolution - 0.2 micrometres
Magnification - x1500
65
What is the difference between transmission and scanning electron microscopes?
- SEM see in 3D, TEM in 2D.
- SEM have a resolution of 5 nm, TEM a resolution of 0.5 nm.
66
What is the maximum resolution and magnification of an TEM microscope?
Magnification - x1,500,000
Resolution - 0.5 nm
67
What is the maximum resolution and magnification of an SEM microscope?
Magnification - x1,500,000
Resolution - 5 nm
68
What are the 3 steps of cell fractionation?
- Homogenisation
- Filtration
- Ultracentrifugation
69
Why does the sample have to be ice-cold?
- To slow down enzyme activity
70
Why does the sample have to be isotonic?
- So the water potential isn't affected
71
Why does the sample have to be buffered?
- To keep the pH constant
- Prevent the enzymes from denaturing
72
What is the pellet?
- The sediment at the bottom of the tube, most dense and heaviest.
73
What is the supernatant?
- The liquid remaining above the pellet
74
What is the order of organelles from heaviest to lightest in ultracentrifugation?
- Nuclei
- Chloroplast
- Mitochondria
- Lysosomes
- Endoplasmic reticulum
- Ribosomes
75
What increases the rate of movement across membranes?
- microvilli - increased surface area for the insertion of carrier proteins which diffusion, facilitated diffusion and active transport can take place
- the number of protein channels and carrier proteins in any given area of a membrane
