CELLS: Eukaryotic Cells Flashcards
1
Q
Describe eukaryotic cells:
A
- Complex
- Distinct nucleus
- Membrane-bound organelles
- Include all animal, plant, algae and fungi cells.
2
Q
Describe prokaryotic cells:
A
- Smaller and simpler
- Eg. bacteria
3
Q
Ultrastructure
A
The internal structure of the cell that makes it suitable for its job.
4
Q
What are algal cells like?
A
A lot like plant cells - have all the same organelles, including cell wall and chloroplasts.
5
Q
What are fungal cells like?
A
A lot like plant cells but with two key differences:
- Cell walls are made of chitin, not cellulose.
- Don’t have chloroplasts as they don’t photosynthesise.
6
Q
What are the cell walls of fungal cells made of?
A
Chitin, glycan and glycoproteins.
7
Q
Why don’t fungal cells have chloroplasts?
A
They don’t photosynthesise.
8
Q
Give examples of fungi:
A
Mushrooms and yeast.
9
Q
Are algae single-celled or multicellular?
A
Can be both.
10
Q
Name the 5 parts of the nucleus:
A
- Nuclear envelope
- Nucleolus
- Nuclear pores
- Chromosomes/chromatin
- Nuclearplasm
11
Q
Nuclear envelope.
A
- Double membrane surrounding nucleus.
- Continuous with ER.
- Often has ribosomes on the surface.
12
Q
What is the nuclear envelope continuous with?
What does it often have on its surface?
A
Continuous with ER and often has ribosomes on surface.
13
Q
What is the role of the nuclear envelope?
A
Controls exit and entry of materials in and out of nucleus.
Contains reactions taking place within nucleus.
14
Q
What is the role of nuclear pores?
A
Allow passage of large molecules, like messenger RNA, out of nucleus.
15
Q
Nucleoplasm.
A
Granular, jelly-like material that makes up the bulk of the nucleus.
16
Q
What do chromosomes consist of?
A
Protein-bound, linear DNA.
17
Q
Nucleolus.
A
- Small spherical region within nucleoplasm.
- Manufactures ribosomal RNA and assembles ribosomes.
18
Q
- Double membrane surrounding nucleus.
- Continuous with ER.
- Often has ribosomes on the surface.
A
Nuclear envelope.
19
Q
Granular, jelly-like material that makes up the bulk of the nucleus.
A
Nucleoplasm.
20
Q
- Small spherical region within nucleoplasm.
- Manufactures ribosomal RNA and assembles ribosomes.
A
Nucleolus.
21
Q
What are the three functions of the nucleus?
A
- Control centre - production of mRNA and tRNA and thus protein synthesis.
- Retain genetic info of cell in form of DNA and chromosomes.
- Manufactures rRNA and ribosomes.
22
Q
List the structures of the mitochondria:
A
- Double-membrane
- Cristae
- Matrix
23
Q
Mitochondria:
A
- Site of aerobic respiration.
- Site of ATP production.
24
Q
Describe the double membrane of the mitochondria:
A
- Inner and outer membrane control entry and exit of material.
- Inner membranen is folded to form extensions - cristae.
25
Cristae.
* Extensions of inner membrane of mitochondria
26
What is the role of cristae?
Provide a large surface area for attachment of enzymes and other proteins involved in respiration.
27
What is the role of the matrix in mitochondria?
* Contains proteins, lipids, ribosomes and DNA that allow mitochondria to control production of own proteins.
* Also contain many enzymes involved in respiration.
28
Suggest the quantity of mitochondria found in cells with high levels of metabolic activity:
Number and size of mitochondria, and their cristae, are high as they are responsible for hte production of ATP.
29
* Site of aerobic respiration.
* Site of ATP production.
Mitochondria:
30
* Extensions of inner membrane of mitochondria
Cristae.
31
Chloroplasts
* Small, flattened structure found in plant and algal cells.
* Site of photosynthesis.
32
List the structures within the chloroplast:
* Double membrane
* Stroma
* Grana
* Lamellae
33
Describe the role of the chloroplast envelope:
A double membrane that is highly selective about what it allows to enter and leave the chloroplast.
34
Grana.
Stacks of up to 100 thylakoids.
35
What is the role of the grana?
Where the first stages of photosynthesis takes place (light absorption).
36
Thylakoids.
Disc-like structures that stack to form grana.
37
What is the role of thylakoids?
Contain the photosynthetic pigment called chlorophyll that aids light absorption.
38
Stroma.
Fluid-filled matrix within a chloroplast.
39
What is the role of the stroma?
Site of second stage of photosynthesis - synthesis of sugars.
40
Lamella.
Thin, flat pieces of thylakoid membrane that links together the Grana.
41
How are chloroplasts adapted to light absorption?
* Granal membranes provide large surface areas for attachment chrolophyll, electron carriers and enzymes that carry out 1st stage of photosynthesis.
* Stroma fluid possesses all enzymes needed to make sugars in 2nd stage.
* Chloroplasts contain DNA and ribosomes so can quickly manufacture proteins needed.
42
* Small, flattened structure found in plant and algal cells.
* Site of photosynthesis.
Chloroplasts
43
Stacks of up to 100 thylakoids.
Grana.
44
Disc-like structures that stack to form grana.
Thylakoids.
45
Fluid-filled matrix within a chloroplast.
Stroma.
46
Thin, flat pieces of thylakoid membrane that links together the Grana.
Lamella.
47
What plants cells would not need chloroplasts?
Root cells - these are underground where light rarely penetrates and so don't photosynthesise.
48
Endoplasmic reticulum
Three dimensional system of sheet-like membranes that spread through the cytoplasm.
49
What is the ER continuous with?
## Footnote
*What does this enclose?*
Outer nuclear membrane.
## Footnote
*Encloses network of tubules and flatterned sacs called cisternae.*
50
What are the two types of ER?
Smooth ER and rough ER
51
RER.
A system of membranes enclosing a fluid-filled space.
Surface is covered with ribosomes.
52
SER.
A system of membranes enclosing a fluid-filled space.
No ribosomes
53
What is the role of the RER?
* Provide large surface area for synthesis of proteins and glycoproteins - ribosomes.
* Folds and processes proteins made at said ribosomes.
54
What is the role of the SER?
* Synthesises, stores and transports lipids.
* Synthesises, stores and transports carbohydrates.
55
Golgi apparatus.
Group of fluid-filled, membrane-bound flattened sacs (cisternae).
56
Three dimensional system of sheet-like membranes that spread through the cytoplasm.
Endoplasmic reticulum
57
A system of membranes enclosing a fluid-filled space.
Surface is covered with ribosomes.
RER.
58
A system of membranes enclosing a fluid-filled space.
No ribosomes
SER.
59
What is often seen at the edges of the golgi apparatus?
Vesicles.
60
What are the 5 functions of the golgi apparatus?
* Add carbs to proteins to form glycoproteins.
* Produce secretory enzymes.
* Secrete carbohydrates, like those used for making cell walls.
* Transport, store and modify lipids.
* Form lysosomes.
61
Where are golgi apparatus especially well-developed?
In secretory cells.
## Footnote
*Like epithelial cells within the intestine.*
62
Golgi vesicles.
Small fluid-filled sacs in the cytoplasm, surrounded by a membrane and produced by golgi apparatus.
63
Group of fluid-filled, membrane-bound flattened sacs (cisternae).
Golgi apparatus.
64
What is the role of golgi vesicles?
Stores lipids and proteins made by golgi apparatus and transports them out of cells.
65
Lysosome.
Round organelle surrounded by a membrane, with no clear internal structure.
## Footnote
*Type of golgi vesicle.*
66
Round organelle surrounded by a membrane, with no clear internal structure.
## Footnote
*Type of golgi vesicle.*
Lysosome.
67
What do lysosomes contain?
The digestive enzymes called lysozymes.
68
What are the 4 functions of lysosomes?
* Hydrolyse material ingested by phagocytic cells (liike white bloods cells and bacteria).
* Exocytosis - releasing enzymes outside cell to destroy surrounding material.
* Digest worn out organelles, so useful chemicals can be re-used.
* Autolysis - complete break down of dead cells.
69
Ribosomes.
* Small organelles that either float free in cytoplasm or attach to RER.
* Made of proteins and RNA.
* Not surrounded by membrane.
70
* Small organelles that either float free in cytoplasm or attach to RER.
* Made of proteins and RNA.
* Not surrounded by membrane.
Ribosomes.
71
Describe the structure of ribosomes:
* Two small subunits each of which contains rRNA and proteins.
72
What is the role of ribosomes?
Site of protein synthesis.
73
What type of ribosomes are found in eukaryotic cells?
80S
74
What type of ribosomes are found in prokaryotic cells?
70S.
75
Cell wall.
A rigid structure that surrounds cells in plants, algae and fungi.
76
What are most cell walls made of?
Cellulose.
77
What are two features of cell walls?
* Consist of a number of polysaccharides, such as cellulose.
* Thin layer **(middle lamella)** which marks the boundary between adjacent cell walls and cements them together.
78
A rigid structure that surrounds cells in plants, algae and fungi.
Cell wall.
79
What are the functions of cell walls?
* Provide mechanical strength to prevent cell bursting due to osmotic entry of water.
* Give mechanical strength as a whole.
* Allow water to pass along it and so contributes to movement of water through the plant.
80
What are the cell walls of algae made of?
Either cellulose or glycoproteins of a mixture of both.
81
Chitin
A nitrogen containing polysaccharide.
82
Glycan.
A polysaccharide.
83
A nitrogen containing polysaccharide.
Chitin
84
A polysaccharide.
Glycan.
85
Vacuole
Fluid-filled sac bounded by a single membrane found in the cytoplasm of plant cells.
86
Cell sap.
A weak solution of sugars and salts.
## Footnote
*Sometimes contains pigements called anthocyanins.*
87
Tonoplast.
The surrounding membrane of a vacuole.
88
What is the role of the vacuole?
* Help to maintain pressure inside cell and keep cell rigid - stops plant wilting.
* Sugars and amino acids may act as temporary food stores.
* Pigments may colour petals to attract pollinating insects.
*
89
Fluid-filled sac bounded by a single membrane found in the cytoplasm of plant cells.
Vacuole
90
A weak solution of sugars and salts.
## Footnote
*Sometimes contains pigements called anthocyanins.*
Cell sap.
91
The surrounding membrane of a vacuole.
Tonoplast.
92
Cell surface membrane.
Membrane found on the surface of animal cells and just inside the cell wall of other cells.
93
What is the cell membrane mainly made of?
Lipids and proteins.
94
What is the role of the cell membrane?
Regulates movement of substances into and out of the cell.
## Footnote
*Has receptor molecules which allow it to respond to chemicals like hormones.*
95
Membrane found on the surface of animal cells and just inside the cell wall of other cells.
Cell surface membrane.
