Cell and Molecular Biology Flashcards
(241 cards)
1
Q
What are the three types of respiration?
A
- External: outside –> alveoli
- Internal: blood –> tissues
- Cellular: o2 + nutrients –> energy + byproducts
2
Q
What is the composition of ATP?
A
adenine, ribose, 3 phosphates
3
Q
What are the important parts of glycolysis?
A
Occurs where: cytosol of cells
Start/end products:
- start = glucose
- end = 2 net ATP (4 formed, 2 used; substrate level phosphorylation), 2 NADH, 2 pyruvate
Critical steps:
- hexokinase: first enzyme invovled in glycolysis; phosphorylates glucose to make glucose-6-phosphate which stops glucose from leaving the cell (rxn irreversible)
- phosphofructokinase (PFK): rate limiting step; takes phosphate off ATP to make ADP to make fructose-1,6-bisphosphate (rxn irreversible and commits glucose to glycolysis)
Require oxygen: anaerobic (no oxygen)
4
Q
What is NADH?
A
electron carrier which has been reduced (gain e-)
5
Q
What is NAD+?
A
electron carrier which has been oxidized (lose e-)
6
Q
What is a kinase?
A
an enzyme that catalyzes the transfer of a phosphate group from ATP to a specified molecule
7
Q
What are the important steps of pyruvate decarboxylation?
A
Occurs where: mitochondrial matrix
Start/end products:
- start = 2 pyruvate, 2 coenzyme A
- end = 2 acetyl-coA, 2co2, 2 NADH
Critical steps:
- pyruvate decarboxylase complex (PDC): catalyzes the reaction between pyruvate and coenzyme A
Require oxygen: anaerobic (no oxygen)
8
Q
How many Co2 and NADH are produced during pyruvate decarboxylation for every glucose?
A
2 Co2
2 NADH
*1 for each pyruvate
9
Q
What are the important steps of the krebs (citric acid cycle; tricarboxylic acid cycle)?
A
Occurs where: mitochondrial matrix
Start/end products:
- start = 2 acetyl-coA
- end = 6 NADH, 2 FADH2, 2 GTP (ATP; substrate level phosphorylation), 4 CO2
Critical steps:
- acetyl-coA merges with oxaloacetate to form citrate and cycle continues with 7 intermediates
Require oxygen: aerobic
10
Q
What are the important steps in the electron transport chain (ETC)?
A
Occurs where: inner mitochondrial membrane
Start/end products:
- start = NADH and FADH2 from glycolysis, pyruvate decarboxylation and citric acid cycle
- 2 NADH (glycolysis); 1 NADH (pyruvate decarboxylation); 6 NADH, 2 FADH2 (krebs)
- end = H20 and ATP (oxidative phosphorylation)
Critical steps:
- carrier proteins I, II, III, IV embedded in inner membrane will recieve electrons from electron transporters (NADH, FADH2) and use that energy to pump protons against their concentration gradient into the inter membrane space
- after all electrons have been passed, the final electron accepter is 1/2 o2 which will combine with the protons to make water
-proton motive force: a gradient which uses ATP synthase to catalyze the reaction of ADP to ATP and pushes a proton from the inter membrane space down the pH/electrical gradient
Require oxygen: aerobic
11
Q
What is the final electron acceptor in the electron transport chain?
A
1/2 oxygen
12
Q
With regards to the proton motive force, what happens when the pH of the intermembrane space is higher than normal?
A
THINK more H+ = more acidic = lower pH
This means there is less cellular respiration happening because the pH is higher and therefore less acidic which means there are less protons being pumped into the intermembrane space via the electron transport chain
13
Q
What makes more ATP? NADH or FADH2?
A
NADH makes more ATP
- 3 ATP per NADH because it enters at complex 1
- 2 ATP per FADH2 because it enters at complex 2
**remember: FADH2 has a 2 so it enters at complex 2
14
Q
What is coenzyme q (ubiquinone)?
A
Can be fully oxidized and fully reduced when passing electrons between the complexes
*carrier protein
15
Q
What is cytochrome c?
A
Has an iron atom which catches and releases electrons between complex III and IV
*carrier protein
16
Q
What is the total energy produced from 1 glucose molecule (prokaryotes and eukaryotes)?
A
~ 36 ATP eukaryotes and ~38 ATP prokaryotes
17
Q
What occurs when the cell doesn’t have adequate oxygen to go through pyruvate decarboxylation, krebs cycle, or ETC?
A
fermentation
18
Q
What are the important steps in fermentation?
A
Occurs where: cytoplasm
ALCOHOLIC FERMENTATION
Start/end products:
- start = pyruvate
- end = ethanol
Critical steps:
- acetaldehyde is final electron accepter
Require oxygen: anaerobic
LACTIC ACID FERMENTATION
Start/end products:
- start = pyruvate
- end = lactate / lactic acid
Critical steps:
- pyruvate becomes reduced to lactate which oxidizes NADH to NAD+
Require oxygen: anaerobic
19
Q
What is the cori cycle?
A
A process in the liver that regenerates glucose from lactate released by muscles to be used again
20
Q
What is a catabolic reaction?
A
- Breaks down larger molecules into smaller molecules
- releases energy
*think CATabolic - you give a cat a toy and it will shred it into smaller pieces
21
Q
What is an anabolic reaction?
A
Builds larger molecules from smaller molecules
- requires energy
22
Q
If cells don’t have glucose, then what are the other sources of energy (and in what order)?
A
- Other carbohydrates
- Lipids
- Proteins
23
Q
What is a monossacharide?
A
single, simple sugar made up of one ring
EX. glucose & fructose
24
Q
What is a disaccharide?
A
two monosaccharides joined together
Ex. Sucrose & lactose
25
What is a polysaccharide?
more than two monosaccharides joined together
Ex. glycogen
26
What is glycogenesis?
formation of glycogen from glucose
27
What is glucogenolysis?
breakdown of glycogen to glucose
28
What is gluconeogensis?
The formation of glucose by non-carobhydrates
29
What is insulin?
hormone released by the pancreas when glucose is in abundance
triggers cells to:
1. make glycogen
2. under glycolysis and make ATP via the rate limiting step (PFK - phosphofuctokinase)
30
What is glucagon?
hormone released by the pancreas when glucose is low (*think "glucose is gone" Glu ca gon)
similar to epinehprine
triggers cells to:
1. glycogenolysis
2. inhibit glycogenesis
31
What occurs during carbohydrate digestion?
1. Begins in mouth via release of salivary amylase enzymes which breakdown polysaccharide chains into smaller polysaccharides or disaccharides
2. products will travel from stomach to duodenum where pancreatic amylase is used to break down into disaccharides
3. then the small intestine releases disaccharidases which breakdown disaccharides into monosaccharides
4. monosaccharides taken up by enterocyte in small intestines
32
What are lipids?
Long hydrocarbon chains
33
What are triglycerides?
glycerol + 3 fatty acid chains
34
What is lipolysis?
breakdown of lipids via lipase enzymes
glycerol can enter the glycolytic pathway and make ATP via glyceraldehyde 3 phosphate (DAP) (G3P) (PGAL)
35
How are fatty acid chains broken down?
Beta-oxidation in the matrix of the mitochondria
breaks off 2 carbons at a time at the 'beta (second)' carbon position
2 carbons broke off make acetyl coA
beta oxidation produces 1 NADH and 1 FADH2
36
What occurs during lipid digestion?
lipids are broken down starting in the duodenum
bile is released from the galbladder which emulsifies fats
pancreas releases pancreatic lipases which break down fats into glycerol and 3 fatty acid chains which become absorbed by enterocytes
37
What are the three types of lipoproteins?
1. chylomicron - leave enterocytes in small intestine and enter lacteals which go to the lympatic and circulatory systems
2. LDL - unhealthy bc low dentistry of proteins which are composed of mostly cholesterol
3. HDL - "healthy" bc high dentisty of proteins
38
What occurs during protein digestion?
1. begins in stomach where pepsin is released to breakdown proteins to smaller polypeptides
2. in small intestine peptidase enzymes (like trypsin and chymotrypsin) and break polypeptides into smaller polypeptides until eventually they become just amino acids
39
What is the difference between an atom and a molecule?
An atom is made up of protons, neutrons and electrons and a molecule is two or more atoms joined together by chemical bonds
40
What are the three main types of bonds?
1. ionic bonds - transfer of electrons from one atom to another where both atoms have different electronegativities
2. covalent bonds - electrons shared between atoms of similar electronegativities
--> polar: unequal sharing of electrons between two atoms of different electronegatitivites; results in formation of a dipole
--> non-polar: equal sharing of electrons between two atoms of identical electronegativity
3. hydrogen bonds - a weak bond between molecules with a hydrogen attached to a highly electronegative atom and is attracted to a negative charge on another molecule (F, O, N) -- pick up the FON
41
What are the 5 most important properties of water?
1. excellent solvent - The dipoles of H2O break up charged ionic molecules, making it easy for water to dissolve substances
2. high heat capacity - The degree in which a substance changes temperature in response to gain or loss of heat. For example, the temperature of a large body of water is very stable in response to temperature changes of the surrounding air; you must add a large amount of energy to warm up this water.
3. ice floats - Water expands as it freezes and becomes less dense than its liquid form. This is explained by the H-bonds becoming rigid and forming a crystal that keeps the molecules separated
4. Cohesion/ Surface Tension - Water is attracted to like substances due to its H-bonds. This strong cohesion between H2O molecules produces a high surface tension that allows for phenomena like water bugs walking on water.
5. Adhesion - water is also attracted to unlike substances. For example, you may wet your finger to easily flip pages of a book. Capillary action describes the ability of a liquid to flow without external forces.
42
What is a monomer?
1 unit
43
What is a polymer?
series of repeating monomers
44
What is the hydroxyl functional group?
OH
polar and hydrophilic
45
What is the carboxyl functional group?
COOH
polar, hydrophilic, weak acid
46
What is the amino functional group?
NH2
polar, hydrophilic, weak base
47
What is the phosphate functional group?
PO4 (3-)
polar, hydrophilic, acid
48
What is the carbonyl functional group?
C=O
polar, hydrophilic
49
What is the aldehyde functional group?
H-C=O
polar, hydrophilic
50
What is the keytone functional group?
R-C=O
polar, hydrophilic
51
What is the methyl functional group?
CH3
nonpolar, hydrophobic
52
What is a monosaccharide?
single sugar molecule
(i.e., glucose and fructose)
*OH down = alpha
*OH up = beta
53
What is a disaccharide?
two sugar molecules joined by a glycosidic linkage (occurs via dehydration reaction)
(i.e., sucrose, lactose, maltose)
54
What is a polysaccharide?
series of connected monosaccharides; polymer. Bonds form via dehydration synthesis and breakdown via hydrolysis.
55
What monosaccharides make up sucrose (disaccharide)?
glucose + fructose
56
What monosaccharides make up lactose (disaccharide)?
glucose + galactose
57
What monosaccharides make up maltose (disaccharide)?
glucose + glucose
58
A polymer of alpha-glucose molecules which store energy in plant cells.
starch
59
A polymer of alpha-glucose molecules which store energy in animal cells
glycogen
60
A polymer of beta-glucose molecules which support the structure of walls for plant cells and wood
Cellulose
61
A polymer similar to cellulose, except each beta-glucose group has a nitrogen containing group (n-acetylglucosamine) attached to the ring. It's also a structural molecule in fungal cells as well as insect exoskeletons.
Chitin
62
What are triglycerides (triacylglycerols)?
structures consisting of three fatty acid chains attached to a glycerol backbone; can be saturated or unsaturated.
- saturated: contain no double bonds and have straight chains are bad for health since the straight chains stack densely and form plaques
- unsaturated: contain double bonds that cause kins in chains; are better for health since chains stack less densely, can be sis or trans
63
What are phospholipids?
comprised of two fatty acid chains and a phosphate group (+R) attached to a glycerol backbone
*are amphipathic which describes a molecule that has both hydrophobic and hydrophilic properties
64
Describes a molecule that has both hydrophobic and hydrophilic properties
amphipathic
65
What are steroids?
comprised of three 6 membered rings and one 5 membered ring include hormones and cholesterol
66
Esters of fatty acids and monohydroxylic alcohols, used as protective coating or exoskeletons (lanolin)
waxes
67
Fatty acid carbon chains with conjugated double bonds and six membered C-rings at each end. Includes pigments which produce colours in plants and animals (i.e., carotenes and xanthophylls)
Carotenoids
68
4 joined pyrrole rings that often complex with a metal
porphyrin
69
What are adipocytes?
Specialized fat cells in two categories
1. white fat cells - composed primarily of triglycerides with a small layer of cytoplasm around it
2. brown fat cells - have considerable cytoplasm, lipid droplets scattered throughout, and lots fo mitochondria
70
Similar to phospholipids but have a carbohydrate group instead of a phosphate group
Glycolipids
71
Lipids are insoluble so they are transported via lipoproteins, which are lipid cores surrounded by phospholipids and apolipoproteins
lipoprotein
72
What happens to cell membrane fluidity in cold weather?
cell membranes become more rigid. In order to avoid cell membrane rigidity, cholesterol and mono and poly unsaturated fatty acids are incorporated into the membrane. The incorporation of these groups increases fluidity.
73
What happens to cell membrane fluidity in warm weather?
Cell membranes become more fluid and flexible. In order to avoid cell membrane collapse, cholesterol is added to restrict movement. The fatty acid tails are saturated so they become straight and pack tightly, thus decreasing fluidity.
74
Polymers of amino acids joined by peptide bonds
proteins
75
What is the structure of an amino acid?
76
What are the four types of proteins?
1. storage proteins - casein in milk, ovalbumin in egg whites, and zein in corn seeds
2. transport proteins - hemoglobin carries oxygen, cytochromes carry electrons
3. enzymes - catalyze reactions in both forward and reverse directions based on the substrate concentration. They do not change the spontaneity fo a reaction
i. enzyme efficiency is determined by temperature and pH
ii. amylase catalyzes reactions that breaks the alpha-glycosidic bonds in starch
4. cofactors - non-protein molecules that assist enzymes; the union of a cofactor + enzyme is called an apoenzyme / apoprotein
i. if the cofactor is organic, it is a coenzyme (ex. vitamins). Cofactors can also be inorganic (ex. metal ions Fe 2+ and Mg 2+)
ii. If a cofactor is covalently bound to an enzyme, it is called a prosthetic group
77
True or False: RNA can sometimes act as an enzyme (ex. ribozyme)
True
78
Formed entirely of amino acids
simple protein
79
functional proteins that act as carriers or enzymes and are examples of simple proteins
albumins and globulins
80
fibrous proteins that have structural function (i.e., collagen) and are examples of simple proteins
scleroproteins
81
simple protein + non-protein
conjugated
82
protein bound to a lipid
lipoprotein
83
protein bound to a carbohydrate
Mucoprotein
84
protein bound to pigmented molecule
chromoprotein
85
protein complexed around metal ion
metalloprotein
86
contains histone or protamine bound to nucleic acid
nucleoprotein
87
What are the 4 levels of protein structure?
1. primary - sequence of amino acids connected by peptide bonds
2. secondary - 3D shape resulting from hydrogen bonding between amino and carboxyl groups of adjacent amino acids (alpha helix or beta sheet)
--> hydrogen bonds, disulfide bonds, van der waals forces
3. tertiary structure - 3D structure that forms due to non-covalent interactions between amino acid R groups (subunit interaction)
--> non covalent interactions include H-bonds, ionic bonds, hydrophobic effect (R groups push away from water), disulfide bonds, and Van Der Waals forces
4. 3D shape of a protein that is grouping of two or more separate peptide chains
88
Are somewhat water soluble, are mostly dominated by tertiary structure, have a diverse range of functions including: enzymatic, hormonal, inter and intracellualr storage and transport, osmotic regulation, and immune response
Globular proteins
89
are not water soluble, are mostly dominated by secondary structure, are made of long polymers, function to maintain and add strength to cellular and matrix structure (ex. collagen or keratin)
Fibrous/Structural Proteins
90
includes proteins that function as membrane pumps, channels, or receptors
Membrane proteins
91
What is protein denaturation?
Occurs when proteins are taken out of their ideal temperature, pH range, or solvent. Protein denaturation means the protein is reversed back to its primary structure and this process is usually irreversible.
92
True or False: Protein denaturation and protein digestion are the same thing
False
Protein denaturation reverses a protein to its primary structure, however protein digestion eliminates all protein structure, including the primary structure
93
What are nucleotides?
Monomers that make up nucleic acids and consist of:
- nitrogenous base
- five carbon deoxyribose sugar
- phosphate group
*don't confuse with nucleosides, which just consist of a sugar and a nitrogenous bases
94
What is a nitrogenous base?
a nitrogen-containing compound that makes up a nucleotide, and can vary based on whether you have DNA or RNA
DNA
A [adenine] T [thymine] G [guanine] C [cytosine]
RNA
A [adenine] U [uracil] G [guanine] C [cytosine]
Purines "Pure As Gold" - 2 rings; adenine, guanine
Prymidines "Cut the Pye" - 1 ring; cytosine, thymine (uracil)
95
True or false: Both DNA and RNA are double stranded
False, RNA is single stranded
96
Describe cell theory
1. all living organisms composed of cells
2. cell is the basic unit of structure, function, and organization
3. all cells arise from preexisting cells
4. cells carry heriditary information
97
What is the central dogma?
DNA -> RNA -> Protein
98
What is a stereomicroscope (light)?
uses visible light to view the surface of a sample
pro - can view living samples
con - has low light resolution compared to a compound microscope
99
What is a compound microscope (light)?
uses visible light to view a thing section of a sample
pro - can view some living samples (single cell layer)
con - may require staining for good visibility
100
What is a phase contrast microscope?
uses light phases and contrast for a detailed observation of living organisms, including internal structures
pro - has good resolution and contrast
con - not ideal for thick samples and produces a "halo effect" around perimeter of samples
101
What is confocal laser scanning microscope and fluorescence?
used to observe thin slices while keeping a sample in tact; common method for viewing chromosomes during mitosis
pro - can observe specific parts of a cell using fluorescent tagging
con - can cause artifacts
102
What is scanning electron microscope?
pro - view surface of 3D objects with high resolution
con - can't use on living samples, preparation is extensive as sample needs to be dried and coated, is costly
103
What is cryo scanning electron microscope?
similar to scanning electron microscope
pro - sample is not dehydrated so you can observe samples in their more 'natural form'
con - can't use on living samples, samples must be frozen which can cause artificats
104
What is transmission electron microscope?
pro - can observe very thin cross sections in high detail and can observe internal structures with very high resolution
con - cannot be used on living samples, preparation of sample is extensive and technique is costly
105
What is electron tomography?
not a type of microscope, but a technique used to build up a 3D model of a sample using TEM data
pro - can look at objects in 3D and see objects relative to one another
cons - same as TEM cons
106
What is centrifugation?
used to prepare a sample for observation or further experimentation. It spins and separates liquified cell homogenates into layers based on density.
- the most order in which cell parts separate is from most dense pelleting first, and least dense separating last
DIFFERENTIAL CENTRIFUGATION
- in cells, the order is, starting from first component to pellet at the bottom and progressively spinning faster, nuclei layer --> mitochondria --> chloroplasts/lysosomes --> microsomes/small vesicles --> ribosomes/viruses/larger macromolecules
DENSITY CENTRIFUGATION
- forms continuous layers of sediment, where insoluble proteins can be found in the pellet while soluble proteins remain in the supernatant, liquid above the pellet
107
Small molecules are assembled into large molecules
anabolic reaction
108
Large molecules are broken down into small molecules
catabolic reaction
109
The rate of formation of reactants and products is equal and there is 0 net production
equilibrium
110
What lowers the activation energy of a reaction, thereby accelerating the rate of the overall reaction?
catalyst/enzyme
111
What is the role of ATP in chemical reactions and metabolic processes?
ATP is a common source of energy, and the compound stores its potential energy in the form of chemical energy
112
What is Km?
Substrate concentration at 1/2 Vmax
113
What are allosteric enzymes?
have both active and allosteric sites for binding
114
What is competitive inhibition?
mimics the substrate and binds the active site, reaction does not complete
115
How do you overcome competitive inhibition?
increase substrate so Km raises but Vmax does not
116
What is non-competitive inhibition?
substance binds to an area other than the active site, reaction does not complete
117
How do you overcome non-competitive inhibition?
increase Vmax but Km stays the same
118
Describe the relationship between Km and binding affinity.
Low Km = high binding affinity
-- only requires a small amount of substrate to become saturated
High Km = low binding affinity
-- large amount of enzymes required to become saturated
119
Phenomenon that occurs where an enzyme becomes more receptive to additional substrate molecules after one substrate molecule binds to an active site
cooperativity
120
What is a channel protein?
provide a passageway through membrane for hydrophilic (water-soluble), polar, and charged substances
121
What is a recognition protein?
type of glycoprotein that is used to distinguish between self and foreign (ex. major histocompatibility complex on macrophage)
122
What are ion channels?
used to pass ions across the membrane and referred to as gated channels in nerve and muscle cells
- voltage-gated: respond to difference in membrane protein
- ligand-gated: chemical binds to open channel
- mechanically-gated: respond to pressure or vibration
123
What are porins?
allow the passage of certain ions and small polar molecules; increase the rate of water passing in kidney and plant root cells
*less specific - if you can fit through the large passage you can go through
124
What are carrier proteins?
specific to movement across the membrane via integral membrane protein; changes shape after binding to specific molecule that enables it to be passed across
125
What are transport proteins?
proteins that can use ATP to transport materials across the membrane; this includes active transport (ATP driven) and facilitated diffusion (does not require ATP)
126
What are adhesion proteins?
attach sells to neighbouring cells and provide anchos for stability via internal filaments and tubules
127
What are the three major components of the cell membrane?
1. phospholipid membrane permeability - allows small, uncharged, nonpolar, hydrophobic molecules to pass freely through the membrane; polar molecules may cross if they are small and uncharged
2. cholesterol - adds rigidity to animal cell membranes under normal conditions and maintains fluidity of the membrane at lower temperatures; sterols provide analogous function in plant cells; prokaryotes do not have cholesterol in membranes but have hopanoids instead
3. glycocalyx - a carbohydrate coat that covers the outer face of the cell wall of some bacteria and the otuer face of the plasma membrane in some animal cells; consists of glycolipids attached to the plasma membrane, and glycoproteins that may serve as recognition proteins
**functions: adhesive capabilities, barrier to infection, marks for cell-cell regonition
128
How do you detatch peripheral membrane proteins?
peripheral membrane proteins are hydrophilic and changing salt concentration or pH to break H-bonding and electrostatic interactions
129
How do you detatch integral proteins?
integral proteins are hydrophobic and can be destroyed using detergent
130
What organelle am I?
Contains chromatin, chromosomes, histones, is the site of ribosome synthesis, and contains nucleoplasm
Nucleus
131
General packaging structure of DNA around proteins in eukaryotes
Chromatin
132
Tightly condensed chromatin when the cell is ready to divide
Chromosomes
133
Serve to organize DNA which coil around it into bundles called nucleosomes; these bundles are wrapped around 8 proteins
Histones
134
Serves as the site of ribosome synthesis
Nucleolus
135
A dense fibrillar network inside of the nucleus of eukaryotic cells that provides mechanical support; helps regulate DNA replication, cell division and chromatin organization
Nuclear Lamina
136
The irregular shaped region within prokaryotic cells that contains all or most of the cell's genetic material
Nucleoid
137
True or False: The nucleoid region is only found in prokaryotes
True, its analogous structure is the nucleus in eukaryotes
138
What organelle am I?
The gel-like substance part of a cell where all metabolic activity occurs and contains the cytosol and organelles
Cytoplasm
*Think of a bowl of jello with candy embedded inside. The cytoplasm is the jello (cytosol) + candy (organelles) and the cytosol is just the jello
139
What are the two subunits of ribosomes in eukaryotes? prokaryotes?
eukaryotes: 60S + 40S = 80S (larger S = heavier)
prokaryotes: 50S + 30S = 70S (smaller S = lighter)
140
Studded with ribosomes and creates glycoproteins by attaching polysaccharides to polypeptides as they are assembled by ribosomes; is continuous with the outer nuclear membrane in eukaryotes
Rough Endoplasmic Reticulum
141
Does not contain ribosomes and serves to synthesize lipids and steroid hormones for export. In liver cells, the smooth ER function to breakdown toxins, drugs, and toxic products via cellular reactions
Smooth Endoplasmic Reticulum
142
Smooth and striated muscle have smooth endoplasmic reticulum's called
Sarcoplasmic reticulum
143
What organelle am I?
Produced from the golgi that contain digestive enzymes with low pH, and functions in apoptosis, and to breakdown nutrients, bacteria and cell debris
Lysosomes
144
What organelle am I?
Transport of various substances in vesicles and has flattened sacs known as cisternae; cis face = incoming vesicles, trans face = secretory vesicles
Golgi
145
What organelle am I?
Common in liver and kidney that function to breakdown substances, fatty acids, and amino acids. Can be used to modify by-products of photorespiration, and can break down fatty acids for energy; can also produce h2o2 to oxidize substrates
Peroxisome
146
What organelle am I?
Made up of tubulin and serves to provide support and motility for cellular activities; is a spindle apparatus which guides chromosomes during division
Microtubules
147
What is the arrangement of microtubules in flagella and cilia?
9+2
9 pairs of microtubules with 2 singlets in the center
148
What organelle am I?
Provides support for maintaining shape, such as keratin
Intermediate filaments
149
What organelle am I?
Made of actin and involved in cell motility; found in skeletal muscle, amoeba pseudopod and cleavage furrows
Microfilament
150
What organelle am I?
Structures that include centrioles and basal bodies are found at the base of each flagellum and cilium and organize their development. Found in a 9x3 array. Cannot be found in plants because they lack centrioles.
Microtubule Organizing Centers (MTOCs)
151
What organelle am I?
Moves materials between organelles or between organelles and the plasma membrane
Transport vacuoles
152
What organelle am I?
Temporary receptacles of nutrients that merge with the cytoplasm in order to break down food.
Central vacuoles
153
What organelle am I?
Location where plants store starch, pigments, and toxic substances such as nicotine
Storage vacuoles
154
What organelle am I?
Found in single-celled protista organisms like amoeba and paramecium; function to collect and pump excess water out of the cell via active transport to prevent bursting
Contractile vacuoles
155
What organelle am I?
Functions to provide support in plants, fungi, protists, and bacteria
Cell Wall
156
What makes up plant cell walls?
Cellulose
157
What makes up fungi cell walls?
Chitin
158
What makes up bacteria cell walls?
Peptidoglycan
159
What makes up archaea cell walls?
polysaccharides
160
What organelle am I?
Found in animals in area between adjacent cells (beyond plasma membrane and glycocalyx); is occupied by fibrous structural proteins, adhesion proteins, and polysaccharides secreted by cells; functions to provide mechanical support, transmits mechanical signals between inside and outside of cells
Extracellular matrix
161
What are focal adhesions?
connection of the ECM to actin filaments in the cell
162
What are hemidesmosomes?
connection of ECM to intermediate filaments like keratin
163
What organelle am I?
Found in plant cells and include chloroplasts, the site of photosynthesis; leucoplasts, which specialize to store starch, lipids, proteins, as amyloplasts, elaioplasts, and proteinoplasts, respectively, and chromoplasts which store carotenoids
Plastids
164
What organelle am I?
Double-layered organelles that make ATP, and serve as the site of fatty acid catabolism, or beta-oxidation; have their own circular DNA and ribisomes
Mitochondria
165
What organelle am I?
Includes microtubules, microfilaments, intermediate filaments; found in eukaryotic cells, aids in cell division, cell crawling, and the movement of cytoplasm and organelles
Cytoskeleton
166
What organelle am I?
A network of organelles and structures, either directly or indirectly connected, that function in the transport of proteins and other macromolecules into or out of the cell; plasma membrane, endoplasmic reticulum, Golgi apparatus, nuclear envelope, lysosomes, vacuoles, vesicles, and endosomes. NOT the mitochondria
Endomembrane System
167
Cell movement occurs via ____, which undulate like snakes, and ____, which beat in a rapid back and fourth motion
Flagella
Cilia
168
Describe water balance within the cell (i.e., tonicity)
Hypotonic - higher concentration of solute inside the cell so water flows in, cell swells and bursts (cytolysis)
Isotonic - concentration of solute inside and outside of the cell is equal, so net movement of water is equal
Hypertonic - higher concentration of solute outside the cell so water flows out, cell shrinks (plasmolysis)
*water follows salt
169
What are the three types of intracellular circulation?
1. Brownian movement - random particle movement due to kinetic energy
2. Cyclosis/streaming - circular motion of cytoplasm around cell transport molecules
3. Endoplasmic reticulum - provides direct channel from plasma membrane to nuclear membrane
170
What are the two types of extracellular circulation?
Diffusion - if cells are in close contact with external environment they can use diffusion for food and respiration. Also can be used for transportation of materials between cells and interstitial fluid
Circulatory System - if cells are far from external environment the circulatory system is used
171
What are anchoring junctions (desmosomes)?
- keratin filaments attached to adhesion plaques
- bind adjacent cells via connecting adhesion proteins
- provides mechanical stability by holding structures together
- examples: skin epithelium, cervix/uterus
172
What are tight junctions?
- completely encircles cell
- produces a seal that prevents passage of materials between cells, thus materials which do enter the cells must pass by diffusion or active transport
- examples: cells lining the digestive tract
173
What are gap junctions?
- narrow tunnels between animal cells (connexins) that prevent cytoplasm of each cell from mixing
- allow passage of ions and small molecules, essentially channel proteins of two adjacent cells
- examples: heart for passing electrical impulses
174
What are plasmodesmata?
- narrow tunnels between plant cells
- narrow tube of endoplasmic reticulum (desmotubule) will exchange material through cytoplasm surrounding the desmotubule
175
What is bulk flow?
collective movement of substances such as blood in the same direction in response to a force or pressure
176
What is passive transport?
The movement of materials across the cell membrane without using cellular energy
177
What is simple diffusion?
when molecules spread from an area of high to an area of low concentration
178
What is facilitated diffusion?
Movement of specific molecules across cell membranes through protein channels
179
What is active transport?
movement of molecules into or out of a cell against a concentration gradient
180
What is secondary active transport?
the use of the electrochemical gradient of one molecule to move a second molecule
181
Antiport
two substances move in opposite directions
182
Symport (cotransport)
two substances move in the same direcrtion
183
What is group translocation?
process that uses energy to chemically alter the substrate during its transport to prevent it from diffusing back out
184
What are the three types of endocytosis (active transport)?
1. Phagocytosis - undissolved (solid) material enters cell and white blood cell engulfs the material as the plasma membrane wraps around the substance
2. Pinocytosis - plasma membrane wraps around dissolved material (liquid)
3. Receptor-Mediated Endocytosis - a form of pinocytosis in which specific molecules called ligands bind to receptors
185
Similar to endocytosis, but encompasses transportation out of a cell
exocytosis
186
What is the equation for Gibbs Free Energy? What can this equation tell us?
ΔG = ΔH - TΔS
G = Gibbs Free Energy
H = Enthalpy
T= Temperature
S = Entropy
This equation can tell us whether a reaction will proceed spontaneously or non-spontaneously
If ΔG is negative, the reaction can occur spontaneously, if ΔG is positive, the reaction is non-spontaneous.
187
What happens to free energy for an exergonic reaction?
Spontaneous
ΔG is negative
free energy is released
188
What happens to free energy for an endergonic reaction?
Non-spontaneous
ΔG is positive
free energy is required
189
True or false: Basal Metabolic Rate (BMR) increases as body size increases
True
190
True or false: An elephant has a higher BMR than a squirrel, but a squirrel would have a higher BMR per kg
True
BMR actually decreases per kg as size goes up
191
What is the relationship between temperature and metabolism?
Increased temperature = increased metabolism
192
What is the relationship between age and metabolism?
Increased age = decreased metabolism
193
True or False: Cellular respiration is an oxidative endergonic process.
False, it is an oxidative exergonic process
194
What is the overall reaction for cellular respiration?
C6H12O6 +6CO2 + 6H2O + ATP
195
Why is there a difference of ATP totals for cellular respiration in eukaryotes and prokaryotes?
Eukaryotes ~ 36 ATP
Prokaryotes ~ 38 ATP
Prokaryotes don't have mitochondria so they do not have to transfer two NADH molecules to the mitochondrial matrix, done via active transport, which costs 1 ATP each
196
What is chemiosmosis?
the use of energy in a H+ gradient to drive cellular work
197
True or False: ATP is a DNA nucleotide
False, it is an RNA nucleotide because it contains a ribose sugar
198
True or False: ATP is an unstable molecule, but becomes more stable when one phosphate group is removed via hydrolysis
True
199
The change from a less stable molecule to a more stable molecule always (releases/requires) energy.
Releases
200
Use oxygen when it's present (more efficient) but switch to fermentation/anareobic respiration if it isn't
Facultative Anaerobe
201
cannot live in the presence of oxygen
obligate anaerobe
202
Obligate aerobe
cannot live without the presence of oxygen
203
Do not use oxygen because they have a fermentative metabolism, but are not harmed by oxygen
Aerotolerant Anaerobe
204
Microaerophiles
require oxygen concentration lower than air
205
True or False: Fats store more energy than carbohydrates per carbon atom
True
206
What is the overall reaction of photosynthesis?
6CO2 + 6H2O --> C6H12O6 + 6O2
207
Describe the process of photosynthesis
1. Pigments (chlorophyll a, chlorophyll b, carotenoids [red, orange, yellow]) absorb energy from the sun and causes electrons to become excited and unstable
2. Electrons re-emit absorbed energy which becomes reabsorbed by nearby pigment molecules (P680 - photosystem 2, P700 - photosystem 1)
3. Antenna pigments (chlorophyll b, carotenoids, phycobilins [red algae], xanthophylls) capture wavelengths that chlorophyll a does not, and pass energy to chlorophyll a where the direct light reactions occur
208
What kind of ring does chlorophyll have
Porphyrin with a Mg atom inside
209
Label the chloroplast
210
The location where H+ accumulates as a result of the ETC in a chloroplast.
thylakoid lumen
211
Suspended within the stroma and their membranes contain the two photosystems, cytochromes and electron carriers
Thylakoids
212
Fluid material; that fills area inside the inner membrane and is the location of the Calvin cycle
Stroma
213
Where does non-cyclic photophosphorylation take place?
Thylakoid membrane
214
Where does cyclic phosphorylation take place?
Stroma lamellae - pieces connecting the thylakoids
215
Where does photolysis take place?
thylakoid lumen
216
Where does chemiosmosis take place in the chloroplast?
thylakoid membrane
217
What happens during non-cyclic and cyclic photophosphorylation?
1. Electrons trapped by P680 in PSII are energized by light
2. Two excited e- are passed to a primary e- acceptor
3. Excited e- enter the ETC (PSII, cytochrome proteins, FE2+ cofactor)
4. Two e- lose energy as they move down the chain
5. ETC ends with PSI/P700 where e- become re-energized by sunlight and passed to another primary e- acceptor
NON-CYCLIC PATH
6. 2 e- pass down a short ETC (ferrodoxin protein), NADP+ + H+ + 2 e- form NADPH
CYCLIC PATH
6. 2 e- from PSI join with protein carriers (cytochrome) from the first ETC and generate 1 ATP as they pass through the chain
7. 2 e- are recycled into PSI and continue to have an option to enter the cyclic or non-cyclic path
218
What occurs during the Calvin cycle?
Carbon fixation (gas --> solid)
1. Carboxylation - 6 CO2 + 6 RuBP form 12 PGA and are catalyzed by RuBisCo (RuBP carboylase)
2. Reduction - 12 ATP + 12 NADPH convert 12 PGA --> 12 PGAL (G3P) and byproducts NADP+ and ADP go into non-cyclic photophosphorylation
3. Regeneration - 6 ATP convert 10 PGAL (G3P) --> 6 RuBP, which allows calvin cycle to repeat
4. Carbohydrate Synthesis - Two remaining PGAL are used to make glucose
219
What happens during chemiosmosis?
potential energy in water is used to make ATP
1. H+ ions released into lumen when water is split by PSII and H+ also released into lumen from stroma by cytochome beween PSII and PSI
2. pH and electrical gradient is created at pH 5 and ATP synthase generates ATP (3 H+ = 1 ATP)
220
True or False: Calvin cycle (dark rxns) occurs primarily at night.
False, calvin cycle occurs the same time as the light rxns. It is referred to as the dark rxns because the reaction is light independent
221
True or False: Calvin cycle is light-independent but it requires ATP and NADPH produced from light-dependent reactions
True
222
What occurs during photorespiration?
Rubisco binds to O2 (oxygen fixation) instead of CO2
and produces NO ATP or glucose
*alternate to C3 photosynthesis
223
What is the purpose of C4 photosynthesis?
1. More efficient - little competition when deciding if rubisco should fix CO2 or O2
2. Minimize photorespiration and water loss (ex. found in hot, dry climates)
224
What occurs during C4 photosynthesis?
1. CO2 enters leaf and moved from mesophyll to bundle sheath cells
2. CO2 combines with phosphoenol pyruvate (PEP) to form oxaloacetate (OAA)
3. OAA converted to malate and transferred from plasmodesmata to bundle sheath which requires conversion of 1 ATP to 1 AMP
4. Malate converted to pyruvate and CO2. CO2 used in calvin cycle and pyruvate converted back to PEP
225
What occurs during CAM (crussulacean acid metabolism) photosynthesis? What is the benefit?
1. PEP carboxylase fixes CO2 + PEP to OAA forming malic acid
2. PEP carboyxlase active during night when stomata are open causing malic acid to accumulate in vacuole
3. During day stomata are closed and malic acid is converted back to OAA which requires 1 ATP and releases CO2 which is used in the calvin cycle
BENEFIT - Can proceed during the day when stomata are closed, reducing water loss (ex. cacti and crassulacean plants)
226
Division of a cell nucleus during mitosis
karyokinesis
227
The division of the cytoplasm during cell division
cytokinesis
228
Label the parts of a chromosome
229
Humans have ____ chromosomes, or ____ homologous pairs.
46
23
230
Humans have a total of ____ chromatids
92
231
Mitosis describes cell division in ____ cells. Meiosis describes cell division in ____ cells.
Somatic (body)
Sex/Germ/Reproductive
232
What are the 5 steps of mitosis?
1. Prophase - nuclease disassembles, nucleolus dissapears, chromatin condenses into chromosome, nuclear envelop breaks down, mitotic spindle forms, microtubules connect to kinetochores
2. Metaphase - chromosomes line up in the middle of the cell (metapheseal plate)
3. Anaphase - shortest step of mitosis where sister chromatids (chromosomes) are pulled by microtubules to opposite poles
4. Telophase - nuclear division occurs, nuclear envelope develops, chromosomes become chromatin and nucleoli reappear
5. Cytokinesis
- ANIMAL CELLS: cleave furrow forms and plasma membrane is pulled towards centre of cells, splitting the cytoplasm
- PLANT CELLS: cell plate forms and merges with the plasma membrane, splitting the cytoplasm
*result is two diploid cells
233
When is a karyotype taken?
metaphase
234
What are the three phases of interphase?
G1 - cell increases in size and proteins and ribosomes are synthesized; most variable in length and the length of the cell cycle depends on this stage
S - DNA synthesis occurs
G2 - rapid cell growth, organelles replicated
235
True or false: More time is spent in mitosis than interphase (G1, S, G2), which comprises about 90% of the cycle.
False, interphase comprises 90% of the cycle
236
What happens at the first check point in the cell cycle?
At end of G1, determines if growth occurred and there are favourable conditions, if no cell enters G0
237
What happens at the second check point in the cell cycle?
At end of G2, checks for sufficient Mitosis Promoting Factor (MPF) levels
238
What happens at the third check point in the cell cycle?
M checkpoint which occurs during metaphase and checks if all chromosomes attached to kinetochores
239
What are the 4 cell cycle regulators?
1. Cyclin-dependent kinases (CDK) - regulate the cell cycle via phosphorylation
2. Growth factors - stimulate cell division (i.e., damaged cell)
3. Density-dependent inhibition - cells stop dividing when surrounding cells density reaches maximum
4. anchorage dependence - most cells only divide when they are attached to an external surface such as neighbouring cells or placed on a culture dish
240
What are the steps of meiosis?
MEOISIS I
Prophase I - nuclease disassembles, nucleolus dissapears, chromatin condenses into chromosome, nuclear envelop breaks down, mitotic spindle forms, microtubules connect to kinetochores, and crossing over (synaptonemal complex forms --> ynapsis [homologous chromosome pairing], crossing over at chiasmata)
Metaphase I - homologous pairs line up along the metaphase plate
Anaphase I - homologues pulled to opposite spoles
Telophase I - nuclear membrane develops, nucleus formed and each cell is haploid
MEOSIS II
Prophase II - nuclear envelope disappears, spindle develops, NO chiasmata or crossing over
Metaphase II - chromosomes align on metaphase plate
Anaphase II - each chromosome pulled to opposite poles
Telophase II - nuclear envelope reappears and cytokinesis occurs, the result is 4 haploid cells
241
How many chromosomes and exist for each part of mitosis and meiosis?
