1
Q
Four parts of the plasma membrane
A
- Phospholipids
- Proteins
- Carbohydrates
- Cholesterol
2
Q
Phospholipids
A
a. Function: separates the inside from the outside of the cell
b. Structure:
i. A phosphate group (polar)
ii. A glycerol molecule
iii. 2 fatty acid chains
3
Q
Membrane fluidity
A
- Fluid = movement
○ Components are floating around
○ Static
○ How solid or liquidy they are based on temperature - Mosaic = many small pieces come together to make a larger component
4
Q
Phospholipids arrange themselves in a bilayer
A
- Polar heads face outward
- Hydrophobic tails face in towards each other
5
Q
Selectively permeable
A
- It allows some molecules to pass through, but not others
○ Selects by
1. Size
□ Small
2. Charge
□ Non polar
6
Q
Effects on membrane fluidity
A
- Temperature
○ Higher temperature = increased fluidity
- More kinetic energy allows more free movement
○ Lower temperature = decreased fluidity, more rigid
- Phospholipids have less energy and tend to pack closer together- Phospholipid Type
○ Unsaturated fatty acid tails = more fluid
- Prevents molecules from packing too tightly
○ Saturated fatty acid tails = more rigid
- Can pack together more together
- Phospholipid Type
7
Q
Proteins
A
- Protein function - cross membrane transport and cell communication
8
Q
Integral proteins
A
Integrated completely into/through the bilayer
1) Cross membrane transport
a) Facilitated diffusion (passive, no energy required)
i) Protein transport through tubes/tunnels call protein channels
b) Active transport (requires energy (ATP) to proceed)
i) Pump ions out to create electrical impulses, creates ATP
- Pump can be used to pump Na out, K out
9
Q
Peripheral proteins
A
Occur only on the exterior of the membrane (on the edges)
1) Act as enzymes, helps hold cell shape, attached to carbohydrates
a) Ones on the outer edge have carbohydrates attached to them
b) Inner ones act as enzymes, help hold cell shape
10
Q
Carbohydrates
A
a. Carbohydrate function - adhesion, cell recognition, and cell signaling
1. Helps communication, regulate themselves, and maintain and develop tissues
2. Allows immune cells to differentiate between body cells and foreign cells (destroy)
b. Only present on the outer surface of the membrane
c. Sometimes the sugars make the cell sticky and it sticks to another cell - adhesion
d. Can also detect particles, if it’s food it’ll bring it into the cell
11
Q
Glycoprotein
A
Polysaccharide attached to a peripheral protein
12
Q
Glycolipid
A
Polysaccharide attached to phospholipid
13
Q
Cholesterol
A
a. Cholesterol function - helps minimize effect of temperature on fluidity
1. Low temps: increases fluidity, keeps phospholipids from packing too tightly by disrupting packing
2. High temps: reduces fluidity, holds phospholipid together, reduces movement
14
Q
Solution
A
When something is dissolved in something else
15
Q
Solute
A
Dissolved particles
16
Q
Solvent
A
The dissolved medium
17
Q
Aqueous solution
A
A solution where the dissolving media is water
18
Q
Like dissolves like
A
Polar solvents dissolve polar solutes
Non polar solvents dissolve polar solutes
19
Q
Tonicity
A
Relative solute concentration
20
Q
Hypertonic
A
Solution with the higher solute concentration
21
Q
Hypotonic
A
Solution with the lower solute concentration
22
Q
Isotonic
A
Two solutions of equal solute concentration
23
Q
Passive transport
A
Requires no energy
Moves with concentration gradient
24
Q
Active transport
A
Requires energy (ATP)
Moves molecules against the concentration gradient
25
Concentration gradient
Region of space over which the concentration of a substance changes
26
Types of passive transport
Diffusion, facilitated diffusion, osmosis
27
Diffusion
Occurs when a solute from an area of high concentration moves down its concentration gradient to an area of lower solute concentration
- Occurs towards the hypotonic solution
28
Equilibrium
The state in which the concentrations of the diffusing substance in the two compartments are the same or become equal
- Movement of molecules does not stop - at equilibrium, there is equal movement of materials in both directions
- No diffusion at equilibrium
29
Factors that affect diffusion rates
- Concentration gradients: greater difference, faster diffusion
- Mass of the molecules - smaller molecules diffuse more quickly
- Temperature - molecules move faster when temperatures are higher
- Surface area - increased surface area speeds up diffusion rates
○ As a cell increases in size, its surface area decreases compared to its volume
- As a cell grows, it becomes less efficient
30
Facilitated diffusion
Passive movement across a membrane of substances down their concentration gradients through the integral membrane proteins
○ channel proteins
○ Ions & small polar molecules
- Important examples: Facilitated diffusion of glucose
31
Osmosis
The passive movement of water across a membrane
- Occurs towards the hypertonic solution
32
Lysis
Osmosis in animal cells
- Loss of salt, too much water, cells will burst
- Cell in hypotonic solution
33
Aquaporins
Osmosis moves across the membrane through protein channels called _____
34
Crenation
Osmosis in animal cells
- Too much salt, cells shrivel
- Cell in hypertonic solution
35
Turgid pressure
Osmosis in plant cells
- Water pressing against inside of the cell wall, provides rigidity
- Cell in hypotonic solution
36
Plasmolysis
Osmosis in plant cells
- Not enough water, too much salt, causes wilting
- Cell in hypertonic solution
37
Osmosis rule
SALT SUCKS
If the area outside the cell has more salt, then the water will be sucked out of the cell toward the salt
38
Bulk transport
Type of active transport - energy is required
- When cells need to import or export molecules/particles that are too large to pass through a transport protein
39
Endocytosis
Importing by bulk transport
40
Exocytosis
Exporting by bulk transport
41
Phagocytosis
Cellular eating
- Cell membrane surrounds a particle and engulfs it
- Solid particles are engulfed by flexible cell extensions: pseudopods
42
Pinocytosis
Cellular drinking (like pinot)
- Fluids and/or dissolved substances are enclosed in vesicles by very fine protrusions called microvilli
43
Receptor mediated endocytosis
Specialized
- Uptake of a specific substance is targeted by binding to receptors on the external surface of the membrane
- Receptors need to be activated
- If the molecule is the right shape, it will activate the receptor
- How toxins and poisons get in the cell
44
Exocytosis
- Vesicles containing substances fuse with the plasma membrane
○ The contents are then released to the exterior of the cell
- A vesicle migrates to the plasma membrane, binds, and releases its contents to the outside of the cell
- Ex: white blood cells engulfing a virus and eliminating it
45
Bioenergetics
The study of energy flow through a living system
46
Metabolism
The totality of an organism's chemical reactions
47
Energy
The capacity to cause change, can be used to do work
48
Kinetic energy
Energy in motion
49
Potential energy
Stored energy
50
Chemical energy
Energy stored in chemical bonds (potential); energy released (kinetic)
51
Exergonic
If energy is released in a chemical reaction, then it is _____
Products of reactions have less free energy than the substrates
ex: digestion, cell respiration
52
Endergonic
Requires an input of energy
Products of these reactions will have more free energy than the substrates
ex: photosynthesis, DNA replication
52
Activation energy
Provides the initial energy required for a reaction to proceed (push to get it started)
- Hump in the diagram
- Heat tends to be main source
53
Transition state
Unstable state when reactants become unstable, which allows the bond(s) to be broken or made
54
Enzymes
Protein catalysts that speed up reactions by lowering required activation energy
55
Enzymes _____ with reactant molecules promoting bond-breaking and bond-forming processes
Bind, not bond
56
Substates
Reactants in an enzymatic
57
When writing an enzymatic reaction, where does the enzyme go?
Above the arrow
58
Active site
The physical location on an enzyme where the substrate binds
(the little opening of the enzyme)
59
Enzyme specificity
Each enzyme only accepts one specific type of substrate, enzymes are reusable
60
How does an enzyme work?
Operates like a little hand, substrates go in, enzyme closes around substrates, products come out
61
Conformation
Enzyme conforms around the substrates
62
Induced fit
The turning on of an enzyme locking the substrate into place (enzyme conforms)
63
Sensitivity of enzymes to their environment
- Activity of an enzyme is influenced by the cell’s environment
- Enzymes operate under relatively stable temperature, pH, and osmotic pressure of an organism’s habitat
○ Same pH, same temperature
○ Ex: if you took an enzyme out of a north pole bacteria and put it in our environment, the enzyme cannot function, needs stability
64
Optimal environment
Optimal chemical environment where the enzyme functions best
65
Denature
When an enzyme loses function due to a change in its conformation
- If the shape of the enzyme is changed, the active site will be disrupted, and the enzyme will no longer be able to function
66
Effects of temperature on enzymes
The optimal temp of an enzyme is dependent on the environment in which it typically functions
67
Effects of pH
Each enzyme has an optimal pH that is dependent on the environment in which it is typically active
68
Cofactors
Non protein helpers that bind to the enzyme's active site or the substrate
○ Two types:
- Inorganic metal atoms - zinc, iron, and copper
- Coenzymes – organic molecules like vitamins
69
Coenzymes
Organic molecules that help an enzyme, often vitamins or derived from vitamins
Ex: biotin
70
Enzyme inhibitor
A substance that blocks the action of an enzyme
Two types: competitive and noncompetitive
71
Competitive inhibition
Substance that resembles the normal substrate competes with the substrate for the active site
72
Relenza
Competitive inhibitor that binds to neuraminidase and inhibits it
- Used to treat the flu, restricts the spread of the virus
73
Competitive inhibitors
When the inhibitor competes with the substrate for the active site
74
Noncompetitive inhibitors
Bind to the enzyme at a different location, causes a conformational change to the enzyme's active site preventing the substrate from binding
75
Cyanide
Noncompetitive inhibitor that prevents ATP production and cellular respiration, leading to eventual death
76
Cell division
Identical replication of cell
77
Prokaryotic cells reproduce via _____
Binary fission
78
Eukaryotic cells reproduce via _____
The cell cycle
79
Binary fission
Asexual reproduction in bacteria - genetically identical daughter cell
One cell becomes two, two become four, keeps doubling
80
Generation time (doubling time)
Time required for one cell to become two (typically around ○ Can vary, but most double within 20-30 minutes
○ Very quick replication
○ Could be much slower (there are exceptions)
81
Exponential growth
Each new fission cycle increases the population by a factor of 2
82
Bacterial cell division by binary fission steps
1. A parent cell - synthesis and activity gearing up for cell division.
2. Chromosome replication and cell enlargement
3. Chromosome division and septation: The chromosomes affix to the cytoskeleton and are separated into the forming cells. The cell lays down a septum that begins to wall off the new cells. Ribosomes are equally distributed to the developing cells.
4. Completion of cell compartments: The septum is synthesized completely through the center, and the cell membrane patches itself so that there are two separate cell chambers.
5. End of cell division cycle: Daughter cells are now independent units
83
Septum
The dividing wall that forms between two new daughter cells during cell division
84
2 phases of the cell cycle
1. Interphase
2. Mitotic phase
85
Interphase
The time for normal growth and preparation for cell division, 90% of the cell cycle is in interphase
(preparing the cell to split)
86
3 stages of interphase
1. G1 Phase – Gap or Growth phase 1
2. S Phase
3. G2 Phase Gap or Growth phase 2
87
G1 Phase – Gap or Growth phase 1
The cell is biochemically active, cytoplasm grows, organelles double
88
S Phase
When DNA synthesis occurs
- DNA makes a new copy of the DNA
- Identical copies of the DNA molecules (sister chromatids) are created
89
G2 Phase Gap or Growth phase 2
Cell doubles in size (animal)
- Plant cells are limited in size by cell wall
Enlarged nucleolus (increased ribosome production)
- Two organelles now, increased protein production
□ Mitosis needs lots of proteins
90
Two stages of mitosis
Karyokinesis and cytokinesis
91
Karyokinesis
Division of the nucleus
92
Cytokinesis
When the cytoplasmic components physically separate into 2 daughter cells
93
4 phases of mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
94
Prophase
- Nuclear envelope breaks down
- Membranous organelles (eg. Golgi complex, endoplasmic reticulum) disperse toward edges of the cell
- The nucleolus disappears
- Centrioles begin migration to poles (animal cells)
- Microtubules of the mitotic spindle form
○ The mitotic spindle is a structure made of microtubule proteins that controls chromosome movement during mitosis
- chromatin fully condenses into chromosomes
Spindle attach at the centromere region of each chromosome
95
Mitotic spindle
A structure made of microtubule proteins that controls chromosome movement
96
Chromatin to chromosome
Short stretches of DNA wrap histone proteins - like a string of beds
- this structure coils to form a chromatin fiber
- Fibrous proteins further pack each maximally compacted chromosome
- Centromere: pinched in region of the duplicated chromosome
- Sister chromatids are genetically identical
97
Metaphase
- Mitotic spindle fully expanded
○ Chromosomes line up along metaphase plate
- Lined up in the middle of the cell
- Look like Xs
○ The metaphase plate forms
○ Sister chromatids remain attached
98
Metaphase plate
An imaginary plate midway between the spindle's two poles
99
Anaphase
- Very quick phase, on the move
- Chromosomes are pulled apart by spindle fibers
○ Chromosomes look like As
- Sister chromatids are separated and move toward opposite poles of the cell
- Other spindle fibers expand elongating the cell
100
Telophase
- Once they're done moving, that's the beginning of telophase
○ As soon as they reach the poles
- Chromosomes reach opposite poles and begin to decondense (unravel) back into chromatin
- Nuclear envelopes form around the chromosomes, and nucleolus appear within the nuclear area
- Mitotic spindle fibers break down
101
Cytokinesis
- Cell division is completed via the physical separation of the cytoplasmic components into two daughter cells.
- Cleavage furrow
○ Cell can be in telophase but cytokinesis is occurring too
102
Cleavage furrowing
Animal cell cytokinesis
○ A cleavage furrow forms at the former metaphase plate in the animal cell.
○ The plasma membrane is drawn in by a ring of actin fibers contracting just inside the membrane.
○ The cleavage furrow deepens until the cells are pinched in two
103
Cell plate formation
- Golgi body makes cellulose filled vesicles and sends them to the center of the dividing cells
- Additional vesicles line up, compact, and fuse creating the cell plate
- Cell plate expands separating the cells
104
Meri stems
Adult stem cells
- conducting lots of mitosis, lots of growth
105
What does prophase look like?
Chromosomes start to appear
- Pairs appear
106
What does metaphase look like?
Chromosomes line up in the middle
- Middle
107
What does anaphase look like?
Chromosomes are pulled to opposite poles
- Apart
108
What does telophase look like?
Nuclear envelopes form around chromosomes
- Two
109
Fermentation
A partial degradation of sugars that occurs without oxygen
110
Anaerobic
No oxygen required
111
How many molecules of ATP does fermentation yield?
2 ATP molecules per sugar molecule
- Super quick but not very efficient
112
Cellular respiration
Degradation of sugar that uses oxygen
113
Aerobic
Uses oxygen
114
How many molecules of ATP does cellular respiration yield?
Around 38 ATP molecules per sugar molecule
- Longer, more complex process
115
What is ATP?
Adenosine triphosphate
116
What is ATP composed of?
Adenosine
- A nitrogenous base
Ribose
- A 5-carbon sugar
- 3 phosphate groups
117
Phosphorylation
When the hydrolysis of ATP releases energy by transferring its third phosphate from ATP from some other molecule
- this transfer is called _____
118
What is fermentation?
Way of harvesting chemical energy without using oxygen or any electron transport chain
119
What does fermentation consist of?
Glycolysis and fermentation
120
What is glycolysis?
Oxidizes glucose into two molecules of pyruvate
○ Nets two molecules of ATP
○ Breaks down 6 carbon sugar, aka glucose, into 3 carbon sugar, pyruvate
121
What is fermentation in terms of what it oxidizes?
Oxidation of NADH to NAD+ and by-products
122
What is the formula for lactic acid fermentation?
Glucose ----> lactic acid + ATP
123
What is the formula for alcoholic fermentation?
Glucose -----> ethanol + CO2 + ATP
124
Outer membrane of the mitochondria
Small molecules can pass freely through the outer membrane
125
Intermembrane space of the mitochondria
This is the area between the inner and outer membranes
126
Inner membrane of the mitochondria
This membrane is impermeable to most molecules. Runs parallel to the outer membrane. Location where most ATP is created
127
Cristae
These are the folds of the inner membrane. Runs perpendicular to the outer membrane. They increase the surface area of the membrane
128
Where does glycolysis take place?
Cytoplasm
129
Matrix
The space within the inner membrane. Contains enzymes, DNA, and ribosomes
130
What does glycolysis produce?
- 2 ATPs *
- 2 NADHs
- 2 Pyruvic acids *
131
Where does the transition step (bridge reaction) take place?
In the mitochondrial membranes
132
What does the transition step (bridge reaction) produce?
- 2 NADHs
- 2 CO2s
- 2 Acetyl CoAs
133
Where does the Kreb's cycle take place?
In the matrix
134
What does the Kreb's cycle prdouce?
- 4 CO2s
- 6 NADHs *
- 2 ATPs
- 2 FADH2s *
* - electron carriers, most important products of krebs cycle
135
Where does oxidative phosphorylation?
In the mitochondrial cristae
136
What does oxidative phosphorylation produce?
- 34 ATPs
- 6 H2Os
137
What is NADH?
High energy electron carrier
138
Two types of autotrophs
Photoautotrophs and chemoautotrophs
139
Photoautotrophs
Use sunlight to make food
- Includes plants, algae, and cyanobacteria
140
Chemoautotrophs
Live where there's no sun, capture energy from inorganic compounds to make food
141
Photosynthesis
Converts solar energy into chemical energy within chloroplasts
- Usually takes place in the leaves of plants
- Photosynthesis can happen anywhere a plant is green
- Some have photosynthetic stems
142
Formula for photosynthesis
Carbon dioxide + water ------light energy-------------> glucose + oxygen + water
143
Shoot system
Anything above the ground
144
Aerial
Above ground portion
145
Vegetative parts
Nonreproductive
- Includes plant organs: leaf, stem
146
Reproductive parts
Flowers, fruits
Flowers have the gametes, sperm inside pollen, egg inside ovule
147
Flowers
Bloom before fertilization, contain pollen and ovule
148
Fruits
Come after fertilization, contain seeds
149
Root system
Subterranean, supports the plants and absorbs water and minerals
150
Subterranean
Below ground
151
Leaf
Main job is photosynthesisSt
152
Stem
Main job is to keep the plant standing up tall, keeps the leaves as close to the sun as possible
- Also to transport water and minerals from the soil to the leaves for photosynthesis
- Conducts water, nutrients, and glucose throughout the plant
153
Root
- Anchors the plant - Absorbs water and minerals, such as nitrogen, potassium, phosphorus, etc
- Transports it up to the leaves for photosynthesis
154
What are the three tissue systems?
1. Dermal tissue
2. Vascular tissues
3. Ground tissues
155
Dermal tissue
The outer protective layer of the plant organs
156
Vascular tissues
Complex conducting tissue, main transporting system
157
Ground tissues
Includes all tissues that are neither dermal nor vascular
158
Two major types of dermal tissues
1. Epidermis
2. Guard cells
159
Epidermis
Always found in a single layer - simple, clear cell
160
Upper epidermis
Lines the top of the leaf
161
Cuticle
Covers the epidermis, made of wax (hydrophobic), clear layer that allows light to penetrate to the cells below while preventing water loss, also protects the leaf from herbivore damage
162
Lower epidermis
Lines the bottom of the leaf, contains guard cells
163
Guard cells
Specialized cells embedded in the lower epidermis, regulate the opening and closing of the stomata by swelling or shrinking
164
Stomata
Space between the guard cells
- Small, regulated openings concentrated on the underside of the leaf
- Helps minimize water loss due to high temperatures on the upper surface of this level
- Water leaves the cell during photosynthesis (transpiration), carbon dioxide can leave through the guard cells too
- If cell needs more water for photosynthesis, guard cells open
- Open guard cells: photosynthesis, closed guard cells: no photosynthesis
- Ex: guard cells close at night
165
Vascular tissue
Mid vein of the leaf, tissues are the tubes inside the mid vein
166
Xylem
Transports water from the roots in the soil up the stem to the leaf
167
Phloem
Transports glucose throughout the plant
168
Mesophyll
Inner tissue of a plant leaf
169
Palisade mesophyll
Highly compacted and organized stacked layer of cells
- Ovular under microscope
- Where most of photosynthesis happens
170
Spongy mesophyll
Less compact and loosely organized cells
- Circular under microscope
- Cells contain chloroplast, additional photosynthesis occurs here
171
What goes into the leaf?
CO2 gets in through stomata
H2O gets into the root xylem, goes up through the xylem, through the stem to the leaf
172
What comes out of the leaf?
Glucose
1. Can stay in cell, utilized for cell respiration to make ATP
- Or stored in the leaf as starch for later use
2. Or travel via the phloem to the roots for storage (starch)
O2 leaves through the stomata
H2O transpires out the stomata
173
Transpiration
Water loss via the stomata
174
Where are the stomata found?
Lower half of the leaf
175
Where is chlorophyll found?
In the mesophyll cells of the leaf
176
What is the double membrane of the chloroplast?
Outer and inner, chloroplast boundary
177
What is the stroma?
Liquid inside chloroplast
178
What is a thylakoid disc?
Individual flattened sac - membrane contains chlorophyll
179
What are grana?
Stacks of thylakoid discs
180
What is the lamella?
Connects and keeps the grana a safe distance from each other and maximizes photosynthesis efficiency
181
What is a starch granule?
Temporary starch storage
181
What is chloroplast DNA?
Circular chromosome that is distinct from the nuclear DNA?
182
What are the ribosomes?
Protein production
183
What are the two photosynthesis reactions?
Light reactions and dark reactions (aka Calvin cycle)
184
What are light reactions?
Occurs in the grana, powered by sunlight
Input H2O
Output O2, ATP, NADPH
185
What are dark reactions (aka Calvin cycle)?
Can happen during the day, just doesn't use light as a power source
- powered by ATP
Input CO2 + NADPH
Output Glucose
186
What are the main colors of light used for photosynthesis?
Purples, blues
187
Why does chlorophyll appear green?
Because the wavelength of green is not used for photosynthesis; it is reflected instead of absorbed
188
What is pigment?
Molecule that absorbs light
189
Where are the photosynthetic pigments found?
In thylakoids
190
What does chlorophyll A reflect?
Bright green light
191
What does chlorophyll B reflect?
Olive green light
192
What are carotenoids?
Antioxidants
193
What does carotene reflect?
Orange light
194
What does xanthophyll reflect?
Yellow light
195
What does anthocyanin reflect?
Purple light
196
What does lycopene reflect?
Red light
197
What is leaf senescene?
Process of a leaf turning off photosynthesis
- Gradual deterioration of leaves due to degradation of chlorophyll
198
What are parasitic plants?
Plants that become dependent on others for their nutrition
- Feed off of living plants
- Contains no chlorophyll
199
What are saprotrophic plants?
Obtain nutrients from dead or decaying materials in the soil
200
What are epiphytes?
Air plants
- require no soil
- all. water and nutrients come from the air
201
What are storage roots?
Roots that store food or water in the soil
202
What are aerial roots?
Roots exposed to the air to aid in the absorption of rain or surface water
203
What is a rhizome?
Modified stem
- Horizontal stem
- Grows just underground near surface of soil
204
What are thorns?
Modified stem with a sharpened point
- thorns are vascularized
205
What are needlelike characteristics?
Shaped like cones, broad leaves
206
What are spines?
A highly modified leaf with stiff rigid structure with a sharp point
- Reduces water loss, protection
207
What are storage leaves?
Leaves that store water or nutrients
208
What are succulent leaves?
Leaves that store water
- desert plants
209
What are bracts?
Floral like leaves found at the bases of flowers or flower stalks
- Attract pollinators
210
What are insect trapping leaves?
Leaves modified to aid in trapping insects
- Help gain nitrogen which is lacking in soils
211
What are sundews?
Leaves covered in glandular hairs that contain digestive enzymes, sparkles attract pollinators, hairs bend and surround insect and digest them
212
What are pitcher plants?
Cone shaped leaves filled with "water", leaves secrete nectar to attract pollinators who fall in, walls are slippery due to extra cuticle waxes built up and bug can't climb out, bugs drown or are digested by enzymes plant secretes
213
What is a venus fly trap?
Leaves hinged at midrib, tiny trigger hairs on inside surface, snap together and digest bug
Bio 101
flashcards
Decks in class (15)
# Cards
