Cell Structure And Function Flashcards
1
Q
What is the cell theory?
A
A theory that states:
All living things are made of cells and their products
New cells are created by old cells dividing in two
Cells are the basic building blocks of life
2
Q
How did cell theory come about?
A
Developed by two microbiologists Schleiden and Schwann in 1839
3
Q
What are the units within cells?
A
Organelles
4
Q
What do cells group together to form?
A
Tissues
5
Q
What do tissues group together to form?
A
Organs
6
Q
What do organs group together to form?
A
Organ systems
7
Q
What do organ systems group together to form?
A
Organisms
8
Q
What is the smallest unit of life?
A
Cells
9
Q
How can you tell the difference between the Golgi body and the endoplasmic reticulum?
A
The ER will be attached to either the cell membrane, or the nucleus
The Golgi body will not be attached to anything
10
Q
Where is the nucleus situated in an animal cell?
A
In the centre
11
Q
Where is the nucleus situated in a plant cell?
A
Near the side
The vacuole takes up the centre space
12
Q
What do all cells have in common?
A
Cell membrane
Cytoplasm
DNA
13
Q
What kinds of cells are prokaryotic?
A
Unicellular organisms
14
Q
What are the two parts of a cell?
A
Living
Non-living
15
Q
What is between cell walls in a plant?
A
The middle lamela
16
Q
What is lignin like?
A
Thick, strong and waterproof
17
Q
What is another name for a cell membrane?
A
Plasma membrane
18
Q
What model describes what the cell membrane looks like?
A
Fluid-mosaic-model
19
Q
What is a cell membrane made of?
A
Phospholipid bilayer
Protein
Carbohydrate chains attached to it
20
Q
What is the phospholipid bilayer like?
A
Has hydrophilic fatty acid tails
Has hydrophobic glycerol heads
21
Q
What do the proteins in the cell membrane do?
A
Help with active and facilitated diffusion
22
Q
What are the carbohydrate chains in the cell membrane for?
A
Communication
23
Q
What is the main function of the cell membrane?
A
To control what comes into the cell and what goes out of the cell
24
Q
What are some other functions of the cell membrane?
A
Transport of nutrients Ingestion Excretion Strength of membrane allows mechanical support Flexibility allows growth and movement
25
What is cytoplasm made of?
90% water
| Dissolved nutrients and waste
26
What does the cytoplasm do?
It exerts pressure on the cell membrane (structure)
Holds nourishment for the organelles
Suspends the organelles
Can be a storage area
27
What does the nucleus contain?
Chromatin network
Nucleolus
Nucleoplasm
Nuclear membrane
28
What does the nucleolus do?
Makes RNA (ribosomes) which make proteins
29
What is nucleoplasm?
The jelly-like liquid inside the nucleus
30
What is the nuclear envelope?
A double membrane surrounding the nucleus
| Is selectively permeable
31
What do nuclear pores do?
Allow substances into the nucleus
32
What does DNA do?
Contains hereditary information
| Contains the "code of life" (tells ribosomes what proteins to make)
33
Where does the DNA in the mitochondria come from?
Only from the mother of an organism
34
What are the two types of ER?
Rough
| Smooth
35
What does the rough ER do?
Protein synthesis
| Membrane production
36
What does the smooth ER do?
Lipid synthesis
37
What is the difference between the rough and smooth ER?
Rough has ribosomes
| Smooth does not
38
What are the two types of ribosomes?
Free ribosomes and polyribosomes
39
What makes vesicles?
Golgi body
ER
Cell membrane
40
When are lysosomes usually produced?
When a cell dies
| When an animal cell has lots of food vacuoles
41
What is a 'floppy' vacuole called?
Flaccid
42
What is the difference between cells called?
Differentiation
43
What is specialisation?
When cells change to perform a specific function
44
What kinds of functions might a cell preform?
Muscle cells contract and relax
Nerve cells conduct impulses
Glandular cells secrete substances
45
What is protoplasm?
The living material in plant and animal cells
46
What are all cells made up of?
Protoplasm
47
What is a cell wall?
A non-living component that animal cells do not have
48
What does protoplasm consist of?
Cytoplasm
| Nucleoplasm
49
What is cytoplasm enclosed by?
The cell membrane
50
What is an organelle?
A membrane-bound structure that is found in the cytoplasm of a cell and that performs a specific function
51
What is the only non-living part of a cell?
The cell wall
52
What are the three parts of the cell wall?
Primary cell wall
Middle lamella
Secondary cell wall
53
What is a primary cell wall?
The first layer in the cell wall
54
Where does the primary cell wall occur?
On the outside of the cell membrane
55
How thick is the primary cell wall?
It is thin
56
What is the primary cell wall made of?
Cellulose fibres that can stretch as the cell grows
57
What is responsible for communication (and transportation) between plant cells?
Pits
| And plasmodesmata
58
What are pits?
Small openings in the cell wall
59
What are plasmodesmata?
Cytoplasmic threads that extend through the pits to adjacent cells
60
What is the middle lamella?
The substance that connects cell walls to one another
61
Where does the middle lamella occur?
Outside the primary cell wall
62
What is the middle lamella made of?
Pectin
63
What is pectin?
A soluble, jelly-like polysaccharide
| It is quite sticky
64
When does the secondary cell wall develop?
As the cells grow older
65
What does the secondary cell wall consist of?
Cellulose fibres
| Lignin
66
What is lignin?
An organic substance that joins cellulose to one another in woody tissues
67
What does lignin do?
Thickens and strengthens the cell walls
68
What are the properties of the secondary cell wall?
It is inelastic
69
What are the pits of the secondary cell wall like?
They are deeper
| Also have plasmodesmata
70
What is the permeability of the cell wall like?
Completely permeable
71
What is the function of the cell wall?
Support structure
Protects the living contents of the plant cell
Gives rigidity to the plant
72
What is sol cytoplasm?
The cytoplasm in a liquid state
73
What is gel cytoplasm?
Cytoplasm in a jelly-like state
74
What is the sol cytoplasm called?
The ground substance (hyaloplasm)
75
What does the ground substance look like?
It looks grey but is actually clear
76
Why does the ground substance look grey?
Due to the organelles and dissolved substances in it
77
What is the function of cytoplasm?
It is the site of all metabolic processes
Cyclosis
Storage
Helps to maintain the shape of the cell
78
What is cyclosis?
The movement of cytoplasm, specifically to circulate substances throughout the cell
79
What is the cell membrane?
The outer living boundary of the cytoplasm
| In an animal cell, it also protects the contents of the cell
80
Why are there proteins embedded in the cell membrane?
For transportation
81
Which part of the phospholipid molecule face inwards?
The tail
82
Which part of the phospholipid faces outward?
The head
83
Why is the cell membrane referred to as fluid?
It is not static (it can move)
84
What is the permeability of the plasma membrane like?
It is selectively permeable
85
Which substances is the phospholipid bilayer impermeable to?
Water-soluble molecules
86
What are examples of water-soluble molecules?
Glucose
Amino acids
Salts
Nucleic acids
87
How do water soluble molecules move through the cell membrane?
Carrier proteins pick them up and drop them on the other side
88
What do other proteins (that pass through the phospholipid bilayer) do?
Form small channels which will only allow certain ions through
89
What are the main compounds that make up cells?
```
Proteins
Carbohydrates
Lipids
Nucleic acids
Water
```
89
What are the two types of cells?
Prokaryotic
| Eukaryotic
89
What is a prokaryotic cell?
A cell in which there are no membrane-bound organelles i.e. Do not have a nucleus
89
What is a eukaryotic cell?
A cell in which there are membrane-bound organelles i.e. Do have a nucleus
89
What is an example of a prokaryotic cell?
Bacteria
89
What are the two types of eukaryotic cells?
Animal
| Plant
89
What kind of surface area is optimal for a cell?
A large surface area is best
89
Why do cells need a large surface area?
It facilitates the movement of substances into and out of the cell
89
What is the optimal volume for a cell?
Relatively small
89
Why must the volume of a cell be relatively small?
It allows for easy diffusion of substances within the cell
89
Are all cells the same?
No, their size, shape and structures change
89
What two forms can cytoplasm exist in?
Sol
| Gel
89
What does the nucleolus look like?
It is a dark body
89
What is the chromatin network?
Tangled threads of DNA
90
What are chromosomes?
Structures that consist of DNA and histones
91
What is the function of the nucleus?
Controls all of the activities of the cell
| Contains DNA
92
What does a mitochondrion look like?
A cylindrically-shaped hollow rod
| It has a double membrane
93
What does the inner membrane of the mitochondrion look like?
It has folds, known as cristae, to increase surface area
94
What is the matrix?
A semi-fluid substance that fills all mitochondria
95
Why does the matrix contain ribosomes?
They synthesis the enzymes that help with the chemical reactions within the mitochondria
96
What is the function of the mitochondria?
Cellular respiration
97
What is cellular respiration?
The process whereby glucose is transformed and energy is released
98
What kind of energy does the cell use?
ATP energy
| Adenosine triphosphate
99
What affects the amount of mitochondria in a cell?
How much energy that cell needs
100
What kind of cell will have more mitochondria?
A muscle cell
101
What are ribosomes?
Small spherical structures that occur in plant and animal cells
102
What do ribosomes consist of?
RNA and proteins
103
Where do ribosomes occur?
ER
Mitochondria
Chloroplasts
In groups in the cytoplasm
104
What are polyribosomes?
Ribosomes that occur in groups in the cytoplasm
105
What is the function of ribosomes?
Protein synthesis
106
What is protein synthesis?
The process during which 51 or more amino acids join to form a protein
107
What is the ER?
A fine membranous network found in plant and animal cells
| It forms a continuous system of canals throughout the cytoplasm
108
What does ER stand for?
Endoplasmic Reticulum
109
Where does the ER occur?
Either connected to the plasma membrane or to the nuclear membrane
110
What is the function of the ER?
Transports substances from one part of the cytoplasm to another
Increases the internal surface area of the cell
111
What does the Golgi body look like?
Stacks of hollow, flat membrane sacs
| These are called cisternae
112
Where does the Golgi body occur?
Plant and animal cells near the nucleus
113
What kind of cells will have more Golgi bodies?
In cells that have a secretory function
114
What is the function of the Golgi body?
It plays a role in producing and processing secretions
| It prepares proteins for transport to other parts of the cell
115
What are examples of secretions that the Golgi body might produce?
Mucous
| Saliva
116
What are plastids?
A type of organelle that occurs only in plant cells
117
What are the three types of plastids?
Chloroplast
Chromoplast
Leucoplast
118
What do chloroplasts look like?
Oval-shaped
| Surrounded by a double membrane
119
Where do chloroplasts occur?
In photosynthesising parts of the plant i.e in the leaves
120
What is stroma?
A fluid matrix that fills the chloroplast
121
What are thylakoids?
Disc-shaped membranes that are contained in the stroma
122
What is a granum?
A stack of thylakoids
123
What is the plural form of granum?
Grana
124
What is another name for thylakoids?
Lamellae
125
What connects two grana?
A membrane known as the intergranum
126
What is another name for the intergranum?
The middle lamella
127
What is embedded in the thylakoids?
Chlorophyll
128
What else does the stroma contain?
Enzymes
Starch grains
Oil droplets
Ribosomes
129
What is the function of the chloroplast?
Photosynthesis
130
What is photosynthesis?
The process whereby radiant energy from the sun is converted into starch granules
131
What is the formula for photosynthesis?
Radiant energy
H2O + CO2 ----------------> C6H12O6 + O2
Chlorophyll
132
What is the formula for cellular respiration?
C6H12O6 + O2 --> H2O + CO2 + ATP energy
133
What are chromoplasts?
Plastids that give plants their orange, red or yellow colour
134
How do chromoplasts occur?
Chloroplasts change into chromoplasts when autumn comes or when fruit ripens
135
How do chromoplasts change the colour of the plant?
With pigments
136
What are chromoplast pigments called?
Carotenoids
137
Why do plants need colour?
To attract bees and birds for pollination
138
What are leucoplasts?
Colourless plastids
139
Where do leucoplasts occur?
In cells that store food in an insoluble form
140
What is the function of leucoplasts?
They become specialised to store food in the form of starch, lipids or proteins
141
What can happen if leucoplasts are exposed to light?
They can turn into chloroplasts
142
What are vacuoles?
Fluid-filled compartments in the cytoplasm
143
What encloses the vacuole?
A membrane called the tonoplast
| It is selectively permeable
144
What is the fluid inside a vacuole called?
Cell sap
145
What is cell sap made of?
Water and dissolved nutrients
146
What are vacuoles like in plant cells?
Large and prominent
147
What are vacuoles like in animal cells?
Small or absent
148
What is it called when the vacuole is not floppy?
Turgid
149
What is the function of the vacuole?
Rigidity
| Colouring (blue, violet and purple)
150
How does vacuole give the cell rigidity?
It exerts turgor pressure on the cell
151
How does the vacuole give colour to the plant?
Through pigments in the cell sap
152
What are the pigments in cell sap called?
Anthocyanins
153
What are four other types of vacuoles?
Contractile vacuoles
Food vacuoles
Vesicles
Lysosomes
154
Where do contractile vacuoles occur?
In unicellular animals
155
What do contractile vacuoles do?
Play a role in osmoregulation
156
What is osmoregulation?
Maintaining water balance
157
Where do food vacuoles occur?
In simple animals
158
What do food vacuoles do?
Play a role in the digestion and storage of food
159
What is the size of vesicles?
Vesicles are small
160
What do vesicles do?
Play a role in the transportation of substances from the Golgi body to parts inside and outside the cell
161
What are lysosomes?
Small vacuoles that are filled with digestive enzymes
162
Where do lysosomes occur?
Only in animal cells
163
What do lysosomes do?
Food digestions, particularly in unicellular animals
164
How do lysosomes digest food?
They fuse with food vacuoles and release the enzymes that digest the food
165
Where do centrosomes occur?
Only in animal cells
| In the cytoplasm near the nucleus
166
What do centrosomes consist of?
Two small cylindrical structures known as centrioles
167
How are the centrioles positioned?
They are close to one another at lie at 90° to each other
168
What does a centriole consist of?
Fibrils
169
What does a fibril consist of?
Three tubular structures known as microtubles
170
What is the function of the centrosome?
The centrioles play a role in mitosis when they form spindle fibres
171
What is the difference between plant and animal cells concerning the cell wall?
Animal: absent
Plant: present
172
What is the difference between plant and animal cells concerning plastids?
Animal: absent
Plant: present
173
What is the difference between plant and animal cells concerning vacuoles?
Plant: large
Animal: small or absent
174
What is the difference between plant and animal cells concerning lysosomes?
Plant: absent
Animal: present
175
What is the difference between plant and animal cells concerning centrosomes?
Plant: absent
Animal: present
176
What is the difference between plant and animal cells concerning shape?
Plant: fixed
Animal: irregular
