Cells Flashcards
1
Q
Description of cell wall
A
Rigid, tough, made of cellulose
2
Q
Description of cell membrane
A
Thin, covering, protects cells
3
Q
Description of cytoplasm
A
Jelly like substance that contains organelles
4
Q
Describe nucleus
A
Dense, ball shaped structure, contains DNA
5
Q
Describe nuclear membrane
A
Thin covering over the nucleus
6
Q
Describe nuleolus
A
Small dark area in the nucleus
7
Q
Describe chromatin
A
In the nucleus, made of DNA and protein, contains genes
8
Q
Describe endoplasmic reticulum
A
Clear, tubular system of tunnels throughout the cell
9
Q
Describe ribosome
A
Small specks made of RNA. Found in cytoplasm or on the endoplasmic reticulum
10
Q
Describe mitochondria
A
Location in the cytoplasm, bean shaped
11
Q
Describe vacuole
A
Large open storage area Smaller in animal cells
12
Q
Describe chloroplast
A
Green structures that contain chlorophyll
13
Q
Describe Golgi body
A
Small bags with tubes connecting them
14
Q
Describe lysosome
A
Small round structures containing enzymes
15
Q
Descibe centriole
A
Small cylindrical
16
Q
Function of cell wall
A
Protects and supports cell
17
Q
Function of cell membrane
A
Protects cell Performs active and passive transport Moves material in and out of cell Communication
18
Q
Function of cytoplasm
A
Pads and supports organelles inside cell Moves by cyclosis
19
Q
Function of nucleus
A
Controls all of cells activities
20
Q
Function of nuclear membrane
A
Covers and protects nucleus
21
Q
Nucleolus
A
Produces ribosomes
22
Q
Function of chromatin
A
Provides instructions for cells activities ( growth, reproduction)
23
Q
Function of endoplasmic reticulum
A
Transports materials like proteins around cells
24
Q
Function of ribosomes
A
Makes proteins
25
Function of mitochondria
Supplies energy or ATP for cell through cell respiration using glucose and oxygen
26
Function of vacuole
Storage tank for food,water, wastes or enzymes
27
Function of chloroplast
Captures sun light and uses it to produce food through photosynthesis
28
Function of golgi body
Packages and stores proteins for use in and out of cell
29
Function of lysosome
Digests older cell parts, food or other objects
30
Function of centriole
Used with spindle apparatus during cell mitosis
31
Do animals, plants or both have cell walls?
Plants
32
Do animals, plants or both have a cell membrane
Both
33
Do animals, plants or both have a cytoplasm
Both
34
Do animals, plants or both nucleus
Both
35
Do animals, plants or both nuclear membrane
Both
36
Do animals, plants or both Nucleolus
Both
37
Do animals, plants or both cromatin
Both
38
Do animals, plants or both endoplasmic reticulum
Both
39
Do animals, plants or both ribosome
Both
40
Do animals, plants or both mitochondria
Both
41
Do animals, plants or both vacuole
Both
42
Do animals, plants or both chloroplast
Plant
43
Do animals, plants or both Golgi body
Both
44
Do animals, plants or both lysosome
Both
45
Do animals, plants or both centriole
Animal
46
What is the cell theory
1. all living things are composed of one or more living cells 2. All cells come from pre existing living cells
47
What are living things characterised by?
Move Grow Replicate/ reproduce Use energy from food Remove waste
48
Describe prokaryotic cells
Approximately 1-10 manometers long Approx 0.2-2 manometers in diameter Single celled organisms Grouped into Bactria and archaea
49
What do prokaryotic cells have?
Cell wall Plasma membrane Cytoplasm Chromosome DNA Plastic DNA Ribosomes Capsule Bactria flagellum Pili
50
What is endosymbiosis theory
Karyotic cells formed when bacterial cell was ingested by another primitive prokaryotic cell
51
What are the four biomacromolecules?
Lipids (eg: triglyceride) Nucleic acid (eg: DNA) Protein (eg: enzymes) Carbohydrates (eg: polysaccharides: starch)
52
What small organic compounds do cells assemble biomacromolecules from?
Simple sugars (monosaccharides: glucose) Fatty acids & glycerol Amino acids Nucleotides
53
Define autotrophs
Build own organic compounds from surrounding inorganic compounds they take in (e.g. photosynthesis)
54
Define heterotrophs.
Build biomacromolecules from existing organic compounds (e.g. chemical energy from food)
55
Define monomers.
Small molecules that act as building blocks for macromolecules
56
Define polymers
Large molecules built up from linking monomers
57
Equation for carbohydrates
nC H₂O
58
3 types of carbohydrates
Monosaccharides: glucose Disaccharides: sucrose = glocose + fructose Polysaccharides: cellulose
59
What does photosynthesis produce?
Glucose (monosaccharide)
60
What are glycoproteins made from?
Carbohydrates and protein
61
Are lipids soluble or insoluble in water?
Insoluble
62
Examples of lipids
Fats & oils; waxes Phospholipids; glycolipids; steroids
63
3 functions of lipids
Store energy (they have approximately twice the amount of energy as carbohydrates) Structural component of membranes Specific biological functions (chemical signal transmission)
64
What are most fats and oils?
Triglyceride (fatty acid & glycerol)
65
What are proteins essential for?
Virtually every cell process
66
What elements are in proteins?
C, H, O, N
67
What are proteins made up of?
Amino acids
68
How many types of proteins are there?
20 (another 2 found only in microbes)
69
What do plants do to their amino acid?
Synthesise it
70
Where do animals get certain amino acids and how many
Diet 9
71
Define proteome
Entire set of proteins produced by a cell
72
How are polypeptide chains made
Amino acids are linked by peptide bonds to form a polypeptide chain
73
What is order of amino acids determined by?
Genes in our chromosomes
74
How are proteins given characteristic features
Polypeptide chains fold
75
Define functional proteome mix
Study of what proteins do in differs cells and tissues
76
What is nucleic acid made up of
DNA and RNA
77
What does nucleic acid undertake
Many tasks at one time
78
Where is nucleic acid located
In nucleus
79
How large is DNA
Approx 2 m in every cell
80
Where is Nucleolus located
Nucleus
81
What does Nucleolus make
Ribosomal RNA ( form of nucleic acid)
82
What does ribosomal RNA make
Ribosomes
83
What is biological significance of low viscosity of water
Flows through small places and capillaries Enables aquatic organisms to move through it without using a lot of energy
84
What is biological significance of colourless and transparency of water
Light penetrates tissue and aquatic environments Allows photosynthesis to continue at considerable depths in aquatic environment
85
What is biological significance of water as universal solvent
Medium for chemical reactions of life Main transport medium in organisms
86
What is biological significance of ice being less dense that water
It floats Insulates underlying water
87
What is biological significance of lipids
Store of concentrated energy Insulation and transport fat soluble vitamins Phospholipids make up cellular membranes
88
What is biological significance of carbs
Major component of most plant cells Source of energy and involved in cellular recognition Can be converted into fats
89
What is biological significance of nucleic acids
Encode genetic info for construction and functioning of organism
90
Biological function of monosaccharides
Energy source for fuelling cellular metabolism Eg glucose for respiration
91
Structure one biological role of starch
Made up of branch cells of glucose Energy storage in compound in plant cells Concentrated in soluble starch granules
92
Structure and bio role of glycogen
Made up of highly branched chains of glucose Energy storage compound in animal tissues
93
Structure and bio role of cellulose
Long un-branched chains of glucose Major structural component of plant cells
94
Structure and bio role chitin
Made up of unbranched chains of n-modified glucose Found in cell walls of fungi Main component of arthropod exoskeletons
95
Basic structure of neutral fat triglyceride
Most phospholipids consist of lesser role attached to fatty acid chains and a phosphate group Phosphate water soluble whilst fatty acid is water repellent ( Hydrophobic )
96
Why do lipids have high energy content
High proportion of hydrogen present in fatty acid chains When molecule metabolised chemical energy released
97
Basic repeating unit of nucleic acids
Nucleotides are repeating monomers that from nucleic acid polymers
98
Describe structure of nucleotides
Sugar molecule Nitrogenous space Phosphate group
99
How info encode in DNA
Base sequence making strand of DNA provides genetic code for cell Precise sequences instruct cell to produce proteins and RNA products required to govern metabolism
100
What makes each of the amino acids in proteins unique
The R group
101
Primary structure of protein
Sequence of amino acids in polypeptide chain
102
What determines primary structure of protein
Order of nucleotides in DNA and RNA
103
How do sequence an composition of amino acids in protein how protein folds up
Differences between amino acids are due to different properties of R group These cause different kinds of intramolecular bonding between amino acids in polypeptide chain which influences way polypeptide chain will fold up
104
Type of bond joining amino acids together
Peptide bond
105
How is peptide bond formed
Condensation reaction
106
Hoe are Di - and polypeptides broken down
Hydrolysis
107
How r proteins involved in structural tissues of the body
Form important component of connective tissues and epidermal structures, cell membranes and in DNA packing
108
How r proteins involved in catalysis metabolic reactions in cells
Enzymes involved in most metabolic reactions
109
How does shape of fibrous protein relate to its functional role
Tertiary structure produces long fibres or sheets with many cross linkages Makes them very tough physically and ideal as structural molecules
110
How does shape of catalytic protein (enzyme) relate to its functional role
3D structure produces globular shape with specific active site critical to their interaction with other molecules and their catalytic activity
111
3 ways in which enzymes differ from other catalysts
Highly specific to particular molecule or bond type Work faster Sensitive to extremes in ph and temperature Generally easily denatured Sensitive to inhibition by metabolic poisons
112
Why are enzymes so effective a low concentrations
Can be reused time and time again Not consumed by reaction
113
How do enzymes catalyse reactions
Influencing stability of bonds in reactants or by providing an alternative reaction pathway
114
How does heat denature enzymes
Changing its tertiary structure usually by disrupting stabilising bonds so that active site can no longer bind a reactant
115
Is every cell and independent unit in an organism
Yes
116
Define plasma membrane
Insoluble boundary of all living cells that maintains contents of cell and regulates movement of substances in and out of cell
117
What have a plasma membrane an cell wall
Plants Bacteria Algae Fungi
118
What do animals only have
Plasma membrane
119
Is a cell wall permeable or impermeable
Permeable to most substances Selectively permeable
120
Why is selective permeability important
Keeps optimal internal environment stable Removes waste Takes in necessary molecules and irons
121
What does plasma membrane control
Exchange of material between internal and external environments of cell
122
What are all cells contained by
A plasma membrane
123
Describe plasma membrane
Flexible and porous Made up primarily of phospholipids and proteins
124
Define hydrophilic head
Phosphate (water absorbing/dissolving)
125
Define hydrophobic end
Fatty acid chains (avoid water/can't dissolve)
126
What is the current accepted model for plasma membrane structure
Fluid mosaic model
127
What does the fluid mosaic model describe membranes as
Lipid bilayer which can flow and change shape Specialised proteins imbedded in lipid in various patterns
128
What is the plasma membrane made more flexible by
Cholesterol in animals Phytosterol in plants and bacteria
129
What are the different proteins imbedded in plasma membrane
Adhesion Transport Receptor Recognition
130
Define adhesion proteins
Help link cells together
131
Transport proteins
Carry molecules across membranes
132
Receptor proteins
Binds hormones and other signal molecules
133
Recognition proteins
Acts as a marker on proteins
134
Antigens
Recognition proteins or glycoproteins combined with a carb chain
135
What do antigens allow immune system to do
Recognise own cells
136
What are the two types of transport
Passive and active
137
Passive transport
Movement of irons and molecules across a membrane from high to low concentration No energy required
138
Active transport
Transport of substances across membrane from low to high concentration Requires energy
139
Diffusion
Spreading out of particles so they are distributed over space available Movement of irons and molecules from high to low concentration until reach equilibrium
140
Diffusion occurs in what and why
Gases and liquids Molecules constantly moving
141
Define met diffusion
Movement of gas and liquid molecules from high concentration to low concentration along a diffusion gradient
142
Why is it called net diffusion
Some molecules will randomly move against the gradient
143
Define passive diffusion
Down a concentration gradient
144
Particle move how
Randomly at equal rates in all directions
145
Facilitated diffusion
Passive process that requires substance to be attached to specific carrier molecule to move across membrane Charged particles Na + CL - Large molecules glucose,amino acids
146
What my carry molecules be
Carrier proteins Channel proteins
147
Osmosis
Movement of water across selectively permeable membranes from regions of low solute to high solute concentration
148
Most important solvent in human body is what
Water (universal solvent)
149
Define solvent
Substance in which another substance can dissolve to create a solution
150
Define solute
Substance that can be dissolved in another substance
151
Dilute solution
High concentration of solvent to solute particles
152
Concentrated solution
Low concentration of solvent to solute particles
153
Hypotonic solution
Low solute concentration Water goes into eukaryotic cells
154
What do Eucaryotes have to remove excess water?
Contractile vacuoles Maintain osmotic balance by collecting water and emptying from self
155
Hypertonic solution
High solute concentration Water leaves eukaryotic solution and cells shrink
156
What do vacuoles in plants contain
Sap
157
Why are turgid cells important in plants
Maintain shape and form
158
Turgid
Tight and rigid from absorbed water
159
Define hypotonic solution
Full turgor on plant cells
160
What happens in Hypertonic solution
Vacuole shrinks Cell becomes flaccid Membrane pulls away from cell wall (plasmolysis)
161
What do transport proteins use ATP for?
To move molecules or ions up their concentration gradient Eg: sodium-potassium pump
162
What is sometimes required during active transport?
Bulk transport of particles across plasma membrane
163
Define endocytosis
Movement of solids or liquids into cell from environment via vesicle formation
164
Define exocytosis
Movement of solids or liquids out of a cell to the environment via vesicle formation
165
What happens for vesicle to be suspended in cell's cytoplasm?
Cell membrane folds around droplet of liquid or solid particle until completely enclosed. Newly formed vesicle pinches off.
166
What are liquids called in regard to endocytosis?
Pinocytosis
167
What are solids called in regard to endocytosis?
Phagocytosis
168
Examples of phagocytosis
Amoeba eating Macrophage engulfing bacteria
169
Define exocytosis
When contents of vesicle inside cell are passed to the outside
170
How does exocytosis occur?
Vesicle that's formed inside cell migrates to cell membrane and fuses with membrane. Contents of vesicle push out into extra cellular fluid
171
Egs of exocytosis
Animals: hormones, mucus, milk proteins, digestive enzymes to other parts of animal Plants: Growth regulators toxins and macromolecules to other parts of plants
172
What does physical and chemical nature of a substance determine
Way in which it will be transported across membranes by cells
173
Chemical factors influencing cell material transport
Uncharged molecules dissolve easily in phospholipid bilayer Charged molecules require transport proteins call iron channels
174
Physical factors influencing cell material transport
Size and charge affect rate of diffusion across membrane
175
Impact of concentration gradient on substances
Diffuse more rapidly the higher the concentration gradient
176
How does surface area to volume ratio affect how cell removes waste and supplies metabolic requirements
The larger surface area to volume ratio the more efficient cell is at removing waste and supplying metabolic requirements
177
How do cells deal with issues of surface area to volume ratio
Changing shape
178
Give example of how cells deal with issues of surface area to volume ratio by changing shape
Root hairs ( increased surface area) Biconcave red blood cells( increase surface area)
179
How big are most human cells
10-15 nano meters
180
Why is there a limit to cell size
All requirements of cell and products of cell must pass across cell membrane Therefore relationship between surface area and volume is important
181
Define metabolism
Process cells carry out to keep organism alive
182
How do cells assemble, rearrange and breakdown organic compounds
Chemical reactions
183
What do internal cellular membranes allow
Many chemical reactions to occur at the same time
184
Function of membrane bound cellular structures
Storage of products Concentration of reactants
185
Increased surface area of membrane bound cellular structures allows for what
More enzymes available for chemical reactions
186
Define metabolic pathways
Ordered enzyme regulated reaction sequences
187
What are main metabolic pathways that transfer energy through living systems
Photosynthesis Respiration
188
What are the two chemical reactions in metabolism
Catabolism Anabolism
189
Define catabolism
Chemical reactions that break down large organic molecules into smaller ones with release of energy
190
Define anabolism
Process of combining small molecules to make larger ones Requires energy Also known as synthesis
191
What is metabolism concerned with
Maintaining balance between energy release and energy utilisation
192
Endergonic reactions use what
Energy
193
Exergonic reactions do what
Release energy
194
Energy for exergonic reactions do what
Fuel endergonic reactions
195
Define enzymes
Proteins that allow chemical reactions to take place
196
Importance of enzymes in body
Reactions would be too slow to be of use
197
Define activation energy
Energy needed to get chemical reactions started
198
How do enzymes effect activation energy
Reduce activation energy needed to begin a reaction
199
Define biochemical pathways
Series of regulated steps in which chemical reactions in cells occur
200
Define catalysts in living organisms
Called enzyme Increase reaction rates
201
What does molecular structure of protein determine
How the perform their functions
202
The active site for an enzymes has a highly specific shape for a what
Particular substrate to which enzyme attaches
203
Define active site
Part of enzyme molecule that combines with substrate
204
Define enzyme substrate complex
When enzyme and substrate combine
205
How are induced fit models different to lock and key models
Enzyme shape not fixed Active site and substrate do not match initially Active site changes shape Chemical properties of substrate change so reaction can occur
206
How fast do enzymes work
Very rapidly
207
How do reactions affect enzymes
They are not destroyed or altered but can be reused
208
What direction of a metabolic reaction can enzymes work in
Either
209
When do enzymes work best
When cellular environment stays within limited range of temp and ph
210
What influences enzyme activity
Temperature
211
Enzymes are very sensitive to what
Ph of medium
212
What happens when temp higher than enzymes range
Enzyme denatured and can't work again
213
What happens when temp lower than enzymes range
Rate of reaction slows down but enzyme not destroyed
214
Define enzyme inhibitors
Substances that slow down or stop enzyme activity
215
What can enzymes be inhibited by
Large amount of substrate Competitive inhibitors binding to active site
216
What do cells use inhibitors for
Control reactions Produce specific amounts
217
What do many enzymes require before they catalyse a reaction
Cofactors Presence of certain irons or nonprotein molecules
218
What do cofactors do to shape of active site
Change it so enzyme combines with substrate
219
Define coenzymes
Cofactors that are nonprotein organic molecules Eg vitamins
220
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