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159 Cards in this Set
- Front
- Back
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What does amino acids conssit of |
*Tetrahedral alpha-carbon connected to an amino group *Carboxyl group *Variable R group |
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What determines the amino acid's properties |
The variable R group
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What do proteins consist of |
Amino acids linked by peptide bonds (amide bonds) |
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What type of characteristics do amide bonds have? |
*Partial double bond characteristics *Lack of rotation *Very stable |
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What are the secondary struture of proteins |
Alpha-helicies Beta-sheets |
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What are the secondary structure of proteins formed through |
Hydrogen bonding interactions between atoms in the backbone of the molecules |
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The most stable tertiary protein structures do what with the amino acids |
Place polar amino acids on the exterior and non polar amino acids on the interior of the protein |
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Why do stable tertiary proteins places polar amino acids on the exterior and non polar amino acids on the interior of the protein? |
Minimizes interactions between nonpolar amino acids and water Optimizes interactions between side chains inside the protein |
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What are carbohydrates? |
Chains of hydrated carbon atoms |
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What is the molecular formula of carboyhydrates |
C(n) H (2n) O (n) |
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What are monosaccharides |
Energy molecules for cells |
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What are examples of monosaccharides |
Glucose Fructose Galactose |
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What are examples of disacchardies |
Maltose Sucrose Lactose |
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What are polysaccharides for? |
Glucose storage Structure |
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What is glycogen |
Glucose storage molecule in animals |
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What is starch
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Glucose storage in plants |
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What is cellulose |
Plant structural molecule |
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Are fats hydorphobic or hydrophilic |
Hydrophobic |
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What are fats used for |
Energy storage (triglyceride) Membrane structure (phospholipids and cholesterol) Hormones (steroids) |
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Hydrolysis of triglyceride produces what |
Three equivalents of fatty acid carboxylates |
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What do the fatty acid carboxylates form in solution? |
Micelles |
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What shape is cholesterol |
Ring-shaped lipid |
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What does cholesterol do |
Stabilize lipid bilayers |
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Steroid hormones are derived from waht |
Chloesterol |
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What are nucleic acids |
DNA and RNA |
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What are the building blocks of nucleic acids |
Nucleotides |
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What are nucleotides comprised of? |
*Pentose sugar *Purine or pyrimidine base *2-3 phosphate units |
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What does the nucleus do |
"Brain" Contains: Nuclear envelope with pores to allow RNA and proteins to pass through and keeps all chromatin and plasmids inside |
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What does the mitochondria do? |
"Powerhouse of the cell" Takes in nutrients and breaks them down for rich molecules of energy for cell Important for cellular respiration keep cell full of energy |
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What does the ribosomes do? |
Make proteins |
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What does rough ER do? |
Protein production Protein folding Quality control Despatch Is studded with ribosomes |
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What does smooth ER do
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Production and metabolism of fats and steroid hormones Not studded with ribosomes and associated with smooth slippery fats |
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What does the golgi apparatus do? |
Process and package macromolecules such as proten and lipids |
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What does lysosomes do |
Digest things |
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What do peroxisomes do?
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Absorb nutrients that the cell acquires |
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What is the rough ER a site for |
Translation of proteins
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What happens to the proteins translated on the rough ER?
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Secreted form the cell Inserted into the membrane Targeted to the lysosomes, ER or Golgi apparatus |
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What are signal sequences |
Specific amino acid sequences that direct protiens in translation to the rough ER and the secretory pathway (rough ER --> Golgi apparatus --> final location) |
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Where does post-translational modification occur? |
Rough ER or in the Golgi apparatus |
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What are al cellular membranes composed of |
Lipid bilayers with distinct hydrophobic and hydrophilic regions |
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What do cellualr membranes do
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Act as selective barriers that regualte which molecules can cross |
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Molecules naturally want to move from regions of (higher/lower) concentration to regions of (higher/lower) concentration |
Higher Lower |
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What is diffusion |
Movement of particles down their concentration gradient |
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What is osmosis? |
Movement of water down its concentration gradient |
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What are examples of hydrophobic molecules? |
O2 CO2 Steroids |
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How do hydrophobic molecules cross the membrane?
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Simple diffusion |
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How do hydrophilic, polar molecules cross the membrane |
With the help of a special membrane protein (channel or a carrier)...facilitated diffusion |
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What does active transport use |
Energy |
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What is active transport? |
Using energy to move molecuels against their concentration gradient (from low concnetration to higher concentration areas) |
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What does primary active transport use? |
ATP directly |
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What does secondary active transport rely on? |
Gradient previously established by a primary active transporter |
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What does Na+/K+ ATPase do? |
Moves three Na+ ions out of hte cell for every two K+ ions it moves into the cell |
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What does Na+/K+ help to do?
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1) Helps establish the resting membrane potential of the cell 2) Helps maintain osmotic balance in the cell 3) Sets up a Na+ gradient that can be used for secondary active transport |
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Wha do G-proteins do |
Help transduce signals from extracellular ligands across the membrane |
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How do G-proteins work? |
They change the level of cAMP or calcium (second messengers) in the cell, which chagnes the metabolic enzyme pathways active in the cell |
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Waht do microtubules form? |
Centrioles Cilia Eukaryotic flagella |
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What do microfilaments participate in? |
Contractile activity |
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Waht do tight junctions help form |
A seal between cells so that the flow of molecules across the entire cell layer is regulated |
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What do desmosomes do? |
Form general adhesions between cells |
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What do gap junctions do? |
Form connections between cells that allow the flow of cytoplasm from cell to cell |
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During the cell cycle, when does DNA replication occur? |
During the S-phase of interphase |
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When does cell division occur duirng the cell cycle? |
Mitosis (M-phase) |
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What are the four major phases of mitosis? |
Prophase Metaphase Anaphase Telophase |
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What does mitosis result in |
Two daughter cells that are identical to each other and identical to the origianl parent cell |
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What does a decrease in free energy mean for the reaction |
That it is spontaneous |
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Does a decrease in free energy mean that the reaction is fast? |
No |
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What does energy of activation of a reaction determine? |
Rate |
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What does a high energy of activation mean for the rate of reaction? |
Slow |
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What does a low energy of activation mean for a rate of reaction? |
Faster rate of reaction |
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Enzymes are biologial _____ |
Catalysis |
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What do enzymes do? |
Increase the rate of reaction by lowering the activation energy |
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How are unfavorable reactions in the cell performed? |
Coupling them with a favorable reaction (such as ATP hydrolysis) |
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How can enzyme activity by controlled |
Covalent modification Proteolytic cleavage Associations Allosteric regulation |
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Where do competitive inhibitors bind? |
Active site of an enzyme |
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Do competitve inhibitors affect V max or Km? |
Increase Km do no affect Vmas |
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Where do noncompetive inhibitors bind? |
Allosteric site of an enzyme |
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What do noncompetitive inhibitors do to Vmax and Km> |
Decrease V mas Change Km |
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What is cellular respiration/. |
*Oxidation of carbohydrates *Reduction of electron carriers *Generation of ATP |
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Where does glycolysis occur |
In cytoplasm |
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What does glycolysis generate |
*2 pyruvate *4 ATP (net of 2) *2 NADH Per glycose |
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Under anaerobic conditons what does the cell do> |
Performs fermentation to regenerate NAD+ so that glycolysis can continue |
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Where does the pyruvate dehydrogenase complex (PDC) function? |
In the mitochondrial matrix |
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What does the PDC do |
Converts pyruvate into acetyl-CoA Generates an NADH |
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Where is the krebs cycle found |
In the mitochondrial matrix
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What does the Krebs cycle generate |
6 NADH 2 FADH2 2 GTP Per glucose |
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Where is the electron transport chain found |
Inner mitochondrial membrane |
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How does the electron transport chain work? |
Starts with the oxidation of the elctron carriers (NADH and FADH2) and ends with the reduction of oxygen and the generation of a proton gradient across the inner mitochondrial membrane |
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Where is ATP synthase found |
In the inner mitochondrial membrane |
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What does ATP synthase use? |
The proton gradient |
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What does ATP synthase |
ATP (2.5 ATP per NADH from the mitochondrial matrix 1.5 ATP per NADH from the cytoplasm 1.5 ATP per FADH2) |
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Do both eukaryotes and prokaryotes perform cellular respiration? |
Yes |
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How does prokaryote cellular respiration differ from eukaryotes? |
Prokaryotes use their plasma membrane for the ETC Generates two more ATP per glucose than eukaryotes |
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Many metabolic pathways converge on the _______ |
Krebs cycle |
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What is photosynthesis? |
Process plants use to convert light to ATP |
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How many steps does photosynthesis occur in |
2 steps |
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What are the two steps of photosynthesis? |
*Light-dependent reactions (generat ATP and NADPH) *Light-independent reactions (generate carbohydrates) |
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What is the fundamental unit of inheritance in clels |
DNA
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Are DNA and RNA polymers? |
Yes |
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What are DNA and RNA made out of? |
Nucleotide monomers |
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What does a nucleotide contain |
*Phosphate group *Sugar *either deoxyribose for DNA or ribose for RNA) *Nitrogenase base *Either a purine (adenine or guanine) or pyramidine (thymmine, cytosine or uracil) |
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What does adenine pair with |
Thymine |
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How many hydrogen bonds between adenine and thymine? |
2 hydrogen bonds |
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What does cytosin alsways pair with |
Guanine |
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How many hydrogen bonds between cytosine and guanine |
Three hydrogen bonds |
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_____ replaces thymine in RNA |
Uracil |
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Wjat does the ribose in RNA have |
An OH group on carbon 2 |
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DNA is ___ in prokaryotes |
Supercoiled |
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What is DNA packaged in eukaryotes |
packaged around histone proteins |
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What are point mutations calssified based on |
Their effect on the amino acid sequence (missense, nonsense or silent) |
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What are frameshift mutations caused by |
Insertions or deletions in the DNA base sequence that affect the reading frame of a gene |
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Are frameshift mutations serious mutations? |
Yes |
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WHy are frameshift mutations serious? |
Because they affect every amino acid codon from the point of mutation on |
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Where does DNa replication occur in the cell cycle? |
S-phase |
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Is DNa replication semiconservative in nature? |
Yes |
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What do helicases do |
Unwind the potential DNA at the origin of replication |
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What do primases do? |
Synthesize an RNA primer |
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What do DNA polymerase do? |
Synthesizes new DNA Proofreads Replaces the RNA primer |
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What do DNA ligase do |
Attach the Okazaki fragments in the lagging strand |
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What is the first part of protein synthesis |
Transcription |
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What is transcription? |
Creation of an RNA transcript by an RNA polymerase that reads the DNA template |
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What is the second part of protein synthesis? |
Translation |
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What is translation? |
Creation of a polypeptide chain by ribosomes that read the mRNA transcript |
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What direction do all nucleotide synthesis (replication of DNA or transcription of RNA) occur? |
5' to 3' |
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Organisms express ______ according to their _____ |
Phenotypes Genotypes |
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What are phenotypes |
Physical characteristics |
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What are genotypes |
Combination of alleles |
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What are the important properties of the side chains include their varying? |
Shape Charge Ability to hydrogen bond Ability to act as acids or bases |
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What are polar, neutral amino acids? |
(DAT Page 21) |
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What are the nonpolar, hydrophobic amino acids |
(DAT pge 21) |
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What are the polar, acidic amino acids? |
(DAT Page 22) |
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What are the polar, basic amino acids? |
(DAT page 22) |
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What do hydrophobic amino acids have |
Either liphatic (alkyl) or aromatic side chains |
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What are the amino acids with aliphatic side chains |
Glycine Alanine Valine Leucine Isoleucine |
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What are the amino acids with aromatic side chains |
Phenylalanine Tyrosine Tryptophan |
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Do hydrophobic residues tend to associate with each other or water |
Each other |
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Where are hydropobic residues found |
On the interior of folded globular proteins, away from water |
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The larger the hydrophobic group, the (less or greater) the hydrophobic force repelling it from water |
Greater |
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What are hydrophilic side chains |
"water-loving" |
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What are the three distinct categories of hydrophilic side chains? |
Acidic Basic Neutral polar residues |
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What are the amino acids with carboxylic acid functional groups? |
Glutamic acid Aspartic acid |
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What is the pKa of carboxylic acid functional group amino acids |
4 |
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What does the "ate" of glutamate or aspartate refer to? |
Anionic (unprotonated) form of the molecule |
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What are the amino acids with basic R-group side chains |
Lysine Arginine Histidine |
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What is the pkas for lysine |
10 |
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What is the pka for arginine |
12 |
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What is the pka for histidine |
6.5 |
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What is unique about the side chain of histidine |
Has a pKa that is close to physiological pH
At pH 7.4 histidine may either be protonated or deprotonated - it is in the basic category but often acts as an acid too Makes it a readily available proton acceptor or donor |
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What are the R-groups of polar amino acids like |
Polar enough to form hydrogen bonds with water but not polar enough to act as an acid or base |
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Are polar amino acids hydrophilic? |
Yes, they will interact with water whenever possible |
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What does the regulatory enzyme kinase do to the serine, threonine and tyrosine amino acids? |
The hydroxyl groups of serine, threonine and tyrosine residues are often modified by the attachment of a phosphate group by kinase. The result is a change in structure due to the very hydrophilic phosphate group Important means of regulating protein activity |
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What are amino acids with a sulfur chain? |
Cysteine Methionine |
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Is cysteine polar or nonpolar |
Polar |
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Is methionine polar or nonpolar? |
Nonpolar |
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Why is proline unique among the amino acids? |
It is bound covalently to a part of the side chain, reacting a secondary alpha-amino group and distinctive ring structure |
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What are the two common types of covalent bonds between amino acids in proteins? |
Peptide bonds Disulfide bridges |
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What are the peptide bonds for? |
Link amino acids together into polypeptide chains |
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What do the disulfide bridges do? |
Link between cysteine R-groups |
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A peptide bond is formed between the _______ of one amino acid and the _____ of another amino acid with a loss of ______ |
*Carboxyl group *α-amino group *water |
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x |
x |
