Section 1 - Terminology Flashcards
1
Q
What is Cell Theory?
A
The theory that the cell is the basic unit of life, all organisms are composed of one or more cells, and all cells come from pre-existing cells.
2
Q
What are Prokaryotic Cells?
A
These cells are smaller in size, contain no nucleus but instead a nucleoid, 70s ribosomes, and no membrane-bound organelles.
3
Q
What are Eukaryotic Cells?
A
These cells are larger in size, contain a nucleus with a nuclear envelope, 80s ribosomes, and membrane-bound organelles.
4
Q
What are Mitochondria?
A
Originally free-living aerobic prokaryotes able to use oxygen to help generate ATP, evolved to be an organelle in the cell which helps to generate ATP.
5
Q
What is Ectosymbiosis?
A
A form of symbiotic behaviour in which an organism lives on the surface of another organism.
6
Q
What is Endosymbiosis?
A
A form of symbiotic behaviour in which an organism lives inside another organism.
7
Q
What is a Model Organism?
A
A living thing selected for intensive study as a representative of a large group of species; they have relatively short life spans, are readily available, reproduce quickly, and are tractable.
8
Q
What is a Genome?
A
All of the DNA or DNA sequences within a cell or an organism.
9
Q
What is a Transcriptome?
A
All the RNA or RNA sequences within a cell or genome.
10
Q
What is a Proteome?
A
All the proteins or protein sequences within a cell or genome.
11
Q
What is an Interactome?
A
All the protein-protein interactions within the cell or organism.
12
Q
What is a Metabolome?
A
All the small molecule metabolites (such as glucose or waste) in the cell or organism.
13
Q
What is a Phenome?
A
All the phenotypes of the cell or organism.
14
Q
What are Nucleic Acids?
A
The genetic material in a cell, organisms’ blueprints.
15
Q
What are Nucleotides?
A
Consists of a nitrogen-containing base, a five-carbon sugar, and one or more phosphate groups; they are the subunits of the nucleic acids.
16
Q
What are Nucleosides?
A
These consist of a nitrogenous base and a five-carbon sugar but not a phosphate group.
17
Q
What are Phosphodiester Bonds?
A
These bonds link nucleotides together.
18
Q
What are Hydrogen Bonds?
A
An intermolecular bond that occurs when hydrogen bonds with O, N, or F.
19
Q
What are Dipole-Dipole Bonds?
A
An intermolecular bond that occurs due to uneven distribution of electrons in a molecule, causing partial positive and negative charges.
20
Q
What are Electrostatic Bonds?
A
A chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion.
21
Q
What are Van Der Waals (London Dispersion) Forces?
A
Weak electrostatic forces that occur when two molecules come in proximity of one another.
22
Q
What are DNA Bases?
A
Adenine, thymine, guanine, cytosine.
23
Q
What are RNA Bases?
A
Adenine, uracil, guanine, cytosine.
24
Q
What is the Major Groove?
A
Occurs where the backbones are far apart.
25
What is the Minor Groove?
Occurs where the backbones are closer together.
26
What are Pyrimidines?
One-ringed nitrogenous bases (C, T, and U).
27
What are Purines?
Two-ringed nitrogenous bases (A and G).
28
What is Denaturation?
The destruction of hydrogen bonds between nucleotide pairs at high temperatures which changes the shape of the DNA.
29
What are 70s Ribosomes?
Ribosomes that are smaller in size and freer in cytoplasm, made of 30s and 50s subunits, used for protein synthesis.
30
What are 80s Ribosomes?
Larger ribosomes in eukaryotic cells that are made up of a smaller 40s subunit and a larger 60s subunit and are often associated with different cell organelles.
31
What is Homeostasis?
The maintenance of relatively stable internal conditions within an organism; can be achieved through physical features, metabolism, and actions and interactions.
32
What are the Characteristics of Living Things?
Made of cells, respond to changes in the environment, can reproduce, exchanges energy and matter with the environment, has metabolism, maintains homeostasis, can grow.
33
What are Archaea?
Extremophile bacteria with DNA in a circular genome, histones present, usually no introns in genes, cell walls not made of peptidoglycan.
34
What are Eubacteria?
True bacteria with DNA in a circular genome, histones absent, usually no introns in genes, and cell walls made of peptidoglycan.
35
What are Eukaryota?
True eukaryotes with DNA in chromosomes, histones present, frequent introns in genes, and sometimes have cell walls that are never made of peptidoglycan.
36
What is a Chloroplast?
Contains chlorophyll used for photosynthesis; only in plants.
37
What are Thylakoids?
Sacs inside the chloroplast that collect light energy from the sun.
38
What is the Rough Endoplasmic Reticulum?
Makes proteins for the cell, and has ribosomes.
39
What is the Smooth Endoplasmic Reticulum?
Produces fats and oils for the cell, and has no ribosomes.
40
What are Ribosomes?
Assembles the proteins.
41
What is the Golgi Apparatus?
Modifies, sorts, and packages proteins from the endoplasmic reticulum for delivery.
42
What is Endocytosis?
A process in which a vesicle is formed on the inside of the plasma membrane and allows water, solutes, and larger molecules that cannot pass through the cell membrane to enter the cell.
43
What is Exocytosis?
A process in which a vesicle fuses with the plasma membrane and releases contents such as waste products and unwanted material out of the cell.
44
What is Cytosol?
The part of the cytoplasm not concentrated within intracellular membranes; is aqueous.
45
What is the Cytoskeleton?
An internal network of fibres that helps to maintain the cell's shape and is responsible for directing cell movements.
46
What are Actin Filaments?
These are the thinnest filaments and provide structural support.
47
What are Microtubules?
These move chromosomes during cell division and are the largest filaments.
48
What are Intermediate Filaments?
These filaments serve to strengthen cells.
49
What are Protozoans?
Free-living, solitary, motile, unicellular eukaryotes.
50
What are Hydrophobic Forces?
Nonpolar surfaces pushed away from water and vice versa.
51
What is Primary Protein Structure?
Amino acid sequence.
52
What is Secondary Protein Structure?
Local folding, alpha helix, beta pleated sheet.
53
What is Tertiary Protein Structure?
Long-range folding, 3D structure of the protein.
54
What is Quaternary Protein Structure?
Multimeric organization, more than one polypeptide chain, multiprotein complexes and molecular machines.
55
What are Disulfide Bonds?
Behaves differently under oxidation and reduction conditions; under oxidation, forms disulfide bonds and you get a strong covalent bond.
56
What is a Polypeptide Chain?
When you put two or more amino acids together to form a peptide bond.
57
What is a Peptide Bond?
A bond formed by the amino group of one amino acid and the carboxyl group of another one via a condensation reaction.
58
What is a Condensation Reaction?
Covalent bond reaction which produces a water molecule.
59
What is a Hydrolysis Reaction?
Uses one water molecule to break a covalent bond.
60
What is the Protein Backbone?
All of the protein’s atoms EXCEPT for the side chains (R groups).
61
What is an Alpha Helix?
In this secondary formation, all the R-groups stick out to form a coil, and in the middle, along the coil, is the backbone of the protein.
62
What is a Beta Pleated Sheet?
Basically shaped like a folded sheet with pleats, sort of like a zig-zag.
63
What is Anti-Parallel (Beta Sheet)?
The segments in the polypeptides alternate the direction in which they're facing.
64
What is Parallel (Beta Sheet)?
All the segments face the same direction.
65
What is an Amphipathic molecule?
A molecule which exhibits both hydrophobic and hydrophilic properties.
66
What is a Hydrophobic molecule?
A molecule that is nonpolar and hates water.
67
What is a Hydrophilic molecule?
A molecule that is polar and loves water.
68
What is a Protein Domain?
Portion of a protein that has its own tertiary structure, often functioning in a semi-independent manner.
69
What are Multiprotein Complexes?
More than one protein get together and work together to achieve a similar goal.
70
What is Proteomics?
The large-scale study of proteins.
71
What are Monosaccharides?
Have the generic formula (CH2O)n where n can be 3–6 and have two or more hydroxyl groups.
72
What are Isomers?
Same molecular formula but different connectivity.
73
What are Disaccharides?
Occurs when two monosaccharides link together via a condensation reaction.
74
What are Polysaccharides?
Occurs when multiple (more than two) monosaccharides link together via a condensation reaction.
75
What are Oligosaccharides?
Basically shorter polysaccharides.
76
What are Fatty Acids?
Composed of a carboxyl group at one end and a hydrocarbon tail at the other; they are nonpolar.
77
What are Triacylglycerols?
Formed when fatty acids link to a glycerol via an ester linkage.
78
What are Phospholipids?
Two of the –OH groups in glycerol are linked to fatty acids, while the third –OH group is linked to phosphoric acid.
79
What are Lipids?
Water-insoluble molecules that are soluble in organic solvents.
80
What are Steroids?
An organic compound with four fused rings in a specific manner.
81
What is a Protein?
Macromolecule built from amino acids that provides cells with their shape and structure and performs most of their activities.
82
What are Enzymes?
Proteins that catalyze covalent bond breakage or formation.
83
What are Transport Proteins?
They provide mechanical support to cells and tissues.
84
What are Structural Proteins?
These proteins carry small molecules or ions.
85
What are Motor Proteins?
They generate movement in cells and tissues.
86
What are Storage Proteins?
These proteins store amino acids or ions.
87
What are Signal Proteins?
They carry extracellular signals from cell to cell.
88
What are Receptor Proteins?
These proteins detect signals and transmit them to the cell's response machinery.
89
What are Transcription Regulators?
These proteins bind to DNA to switch genes on and off.
90
What are Special Purpose Proteins?
These proteins have various highly specialized and specific functions.
91
What are the Functions Carried Out By Proteins?
Catalysis, muscle contraction, cytoskeleton, cell adhesion, membrane transport, immunity, tensile strengthening, blood clotting, transport of nutrients and gases, receptors, hormones, and packing of DNA.
92
What are Chaperone Proteins?
Proteins whose job is to aid other proteins to make protein folding more efficient.
93
What are Amyloid Structures?
A protein aggregate with a cross-β sheet structure, characterized by β-strands that run perpendicular to the fibril axis.
94
What are Prions?
Proteins that can cause fatal brain diseases in humans and animals and are considered infectious.
95
What is a Dimer?
Two identical, folded polypeptide chains form a symmetrical complex of two protein subunits.
96
What is Feedback Inhibition?
A form of metabolic control in which the end product of a chain of enzymatic reactions reduces the activity of an enzyme early in the pathway.
97
What does Allosteric mean?
Describes a protein that can exist in multiple conformations depending on the binding of a molecule.
98
What is Protein Phosphorylation?
The covalent addition of a phosphate group to a side chain of a protein, catalyzed by a protein kinase.
99
What is a Protein Kinase?
Enzyme that catalyzes the transfer of a phosphate group from ATP to a specific amino acid side chain on a target protein.
100
What is a Protein Phosphatase?
Enzyme that catalyzes the removal of a phosphate group from a protein.
101
What is a GTP-Binding Protein?
Intracellular signaling protein whose activity is determined by its association with either GTP or GDP.
102
What is a Protein Machine?
Assembly of protein molecules that operates as a cooperative unit to perform a complex series of biological activities.
103
What is a Scaffold Protein?
Protein with multiple binding sites for other macromolecules, holding them in a way that speeds up their functional interactions.
104
What is a Biomolecular Condensate?
A large aggregate of phase-separated macromolecules that creates a region with a special biochemistry.
105
What is Chromatography?
Technique used to separate the individual molecules in a complex mixture on the basis of their size, charge, or ability to bind to a particular chemical group.
106
What is Affinity Chromatography?
A separation method based on a specific binding interaction between an immobilized ligand and its binding partner.
107
What is Gel Electrophoresis?
Technique for separating a mixture of proteins or DNA fragments by placing them on a polymer gel and subjecting them to an electric field.
108
What is Mass Spectrometry?
An analytical technique that is used to measure the mass-to-charge ratio of ions.
109
What is NMR Spectroscopy?
The study of molecules by recording the interaction of radiofrequency electromagnetic radiations with the nuclei of molecules.
110
What is X-Ray Crystallography?
Technique used to determine the three-dimensional structure of a protein molecule by analyzing the diffraction pattern.
111
What is Cryo-EM?
Technique for observing the detailed structure of a macromolecule at very low temperatures.
112
What is the Human Genome?
Approximately 20k protein-coding genes spread across 23 pairs of chromosomes.
113
What is Nonrepetitive DNA?
Sequences that help determine which DNA gets transcribed and how much.
114
What is an Intron?
A segment of a DNA or RNA molecule which does not code for proteins.
115
What is an Exon?
Any part of a gene that will form a part of the final mature RNA produced by that gene.
116
What are Mobile Genetic Elements?
Sequences that sometimes cut themselves out of DNA, sometimes make a copy, sometimes paste themselves back.
117
What are DNA Only Transposons?
DNA sequences that move from one location on the genome to another.
118
What are Retrotransposons?
Genetic elements that move within a genome by converting RNA into DNA.
119
What are LINEs?
Sequences generally greater than or equal to 500 base pairs.
120
What are SINEs?
Sequences which are typically less than 500 base pairs.
121
What is Eukaryotic Genome Packing?
In humans, six billion base pairs per cell, located in the nucleus.
122
What is FISH?
A technique used to identify DNA sequences on chromosomes using fluorescent dyes.
123
What is a Karyotype?
A complete set of chromosomes ordered from longest to shortest.
124
What is G1?
The stage in interphase where the cell produces new cells and proteins.
125
What is G2?
The stage in interphase where the cell produces organelles and structures needed.
126
What is the size of the nucleus in a cell?
About 6 micrometers in diameter.
127
What is FISH?
A technique used to identify DNA sequences on chromosomes by attaching fluorescent dyes to small pieces of DNA and using a microscope to observe binding.
128
What is a karyotype?
A complete set of chromosomes ordered from longest to shortest.
129
What occurs during the G1 phase of interphase?
The cell produces new cells and proteins.
130
What happens in the G2 phase of interphase?
The cell produces organelles and structures needed for cell division.
131
What is interphase?
The preparatory stage for cell division, comprised of the G1, G2, and S phases.
132
What occurs during the Synthesis phase of interphase?
The cell synthesizes (replicates) an entire copy of its DNA.
133
What is mitosis?
The process where the cell divides, consisting of prophase, metaphase, anaphase, telophase, and cytokinesis.
134
What are centromeres?
The center of the DNA where microtubules connect during mitosis.
135
What happens during prophase?
The first stage in mitosis where chromatin condenses to form a chromosome with two sister chromatids.
136
What occurs during metaphase?
The chromosomes move to the middle, and mitotic spindles attach to the centromere.
137
What happens in anaphase?
Sister chromatids split into individual chromosomes and are pulled to opposite poles.
138
What is telophase?
The final phase of mitosis where the cell begins to divide into two.
139
What is cytokinesis?
The splitting of the cell.
140
What is chromatin?
Genetic information contained inside the nucleus.
141
What does 'Beads On a String' refer to?
DNA wrapped around protein beads about 147 nucleotides long with a histone octamer.
142
What are core histones?
Eight proteins (2 H2A, 2 H2B, 2 H3, and 2 H4).
143
What is a nucleosome core particle?
Core histones plus DNA wrapped around it, excluding linker DNA or H1.
144
What is a nucleosome?
Nucleosome core particle plus H1 and linker DNA.
145
What are histones?
Small proteins rich in lysine and arginine that neutralize the negative charge of DNA.
146
What is a linker histone (H1)?
A histone that clips the DNA on the nucleosome and is essential for DNA stability.
147
What is heterochromatin?
Highly condensed chromatin that includes meiotic and mitotic chromosomes.
148
What is constitutive heterochromatin?
Heterochromatin that is always present.
149
What is facultative heterochromatin?
Heterochromatin that is temporarily present.
150
What is euchromatin?
Relatively non-condensed chromatin, with varying levels of activity.
151
What is quiescent euchromatin?
Euchromatin that does not actively use its genes.
152
What is active euchromatin?
Euchromatin that frequently uses its genes.
153
What is DNA replication?
The process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules; it is semi-conservative.
154
What are mother strands?
The original template strands before replication.
155
What are daughter strands?
The new template strands formed after replication.
156
What is conservative replication?
A type of replication where one daughter strand has both parental strands, and the other has two new strands.
157
What is semi-conservative replication?
A type of replication where both daughter strands receive one new strand and one parent strand.
158
What are Okazaki fragments?
Short DNA segments created during DNA replication on the lagging strand.
159
What is the leading strand?
A strand of DNA synthesized continuously in the same direction as the replication fork.
160
What is the lagging strand?
A strand of DNA synthesized in small fragments during replication.
161
What is exon shuffling?
The process where existing genes are broken and rejoined to create a hybrid gene.
162
What is transposition of mobile genetic elements?
DNA sequences that can move from one chromosomal location to another, altering gene activity.
163
What is horizontal gene transfer?
The transfer of DNA from one cell's genome to another, even across species.
164
What is conserved synteny?
The preservation of gene order in the genomes of different species.
165
What is in situ hybridization?
A technique that separates and identifies specific DNA or RNA sequences in their normal location.
166
What is the replication origin?
The site where DNA replication begins, rich in adenine and thymine.
167
What are telomeres?
Structures that mark the end of each chromosome.
168
What is cohesin?
The SMC complex that organizes interphase chromosomes and holds sister chromatids together.
169
What is condensin?
A ring-shaped SMC protein complex that compacts duplicated chromosomes for segregation.
170
What are chromatin-remodeling complexes?
Large protein machines that change the position of nucleosomes on DNA using ATP hydrolysis.
171
What are histone-modifying enzymes?
Enzymes that modify histone substrates after translation, affecting gene expression.
172
What is DNA repair?
The process that cells use to fix damage to their DNA.
173
What are initiator proteins?
Proteins that bind to the origin of replication and help helicase bind, requiring ATP.
174
What is helicase?
An enzyme that unwinds and separates DNA strands by breaking hydrogen bonds.
175
What are single strand proteins?
Proteins that keep the strands separated after helicase has unwound them.
176
What is a bound primer?
A short sequence of nucleotides with a free 3’ OH required for DNA polymerase to begin.
177
What is a primosome?
A protein complex that creates RNA primers for DNA replication.
178
What is a sliding clamp?
An enzyme that helps hold the polymerase on the DNA.
179
What is (DNA/RNA) primase?
An enzyme that creates short RNA primers to initiate DNA replication.
180
What is DNA polymerase?
Enzymes that create DNA by adding nucleotides together.
181
What is ligase?
An enzyme that seals nicks between Okazaki fragments, forming a continuous DNA strand.
182
What is a replisome?
A molecular machine formed by various proteins involved in DNA replication.
183
What is supercoiling?
When DNA twists upon itself due to torsional stress.
184
What is topoisomerase?
Enzymes that prevent DNA supercoiling by cutting and rejoining DNA strands.
185
What is telomerase?
An enzyme that fixes the loss of sequence information by extending the lagging strand.
186
What is 3' to 5' exonuclease?
A mechanism that removes misincorporated nucleotides in DNA.
187
What is strand-directed mismatch repair?
A process that corrects DNA errors by distinguishing the newly synthesized strand from the template strand.
188
What is the MutS protein?
A protein that recognizes DNA mismatches and recruits MutL.
189
What is MutL nuclease?
A protein that initiates strand removal after detecting the sliding clamp.
190
What are pyrimidine dimers?
Two stacked pyrimidines that disrupt DNA replication, usually caused by UV radiation.
191
What is depurination?
A reaction that breaks the link between sugar and base in DNA, occurring about 500 times a day.
192
What is deamination?
A reaction specific to cytosine that converts it to uracil, occurring about 500 times per day.
193
What is base excision repair (BER)?
A process where uracil is removed from DNA, followed by nucleotide replacement and sealing.
194
What is nucleotide excision repair (NER)?
A process that cuts out a region of nucleotides, removes the helix, and fills the gap with new nucleotides.
195
What is nonhomologous end joining (NHEJ)?
A quick and less accurate way to repair double-stranded breaks, resulting in deletion of DNA sequences.
196
What is homologous recombination (HR)?
A type of double-stranded repair using information from a homologous chromosome.
197
What are genes?
Segments of DNA necessary for the synthesis of a protein or RNA.
198
What is RNA transcription?
The process of adding RNA nucleotides from 5' to 3' without a primer.
199
What is a sigma factor?
A protein that helps start transcription in bacteria by binding to DNA.
200
What is RNA polymerase?
An enzyme that synthesizes RNA from a DNA template.
201
What is a promoter sequence?
+1 is the first nucleotide transcribed; the nucleotide before is -1.
202
What is upstream in transcription?
Moving in the negative direction from the promoter sequence.
203
What is downstream in transcription?
Moving in the positive direction from the promoter sequence.
204
What are promoter consensus sequences?
Models for DNA binding sites made up of common base pairs in promoter regions.
205
What are terminator sequences?
Regions in DNA rich in Gs and Cs followed by As, signaling the end of transcription.
206
What is telomerase RNA?
RNA component of telomerase.
207
What is miRNA?
RNA that inhibits protein synthesis.
208
What is RNA polymerase I?
In eukaryotes, it synthesizes most rRNA genes.
209
What is RNA polymerase II?
In eukaryotes, it synthesizes all protein-coding genes and miRNA genes.
210
What is RNA polymerase III?
In eukaryotes, it synthesizes tRNA genes and 5S rRNA genes.
211
What is the TATA box?
A highly conserved sequence found ~30 bp upstream from the transcription start site.
212
What is TFIID?
A transcription factor at the 2D subunit.
213
What are activator proteins?
Proteins that speed up transcription by binding to enhancers.
214
What are tandem repeats?
Amino acid sequences repeated multiple times.
215
What is the RNAP II tail?
The carboxyl terminal domain of the largest subunit, essential for viability.
216
What is splicing?
The process of removing introns from RNA.
217
What is a spliceosome?
An enzyme that facilitates the splicing of RNA.
218
What is abnormal splicing?
Occurs when nucleotide changes disrupt intron splicing sites.
219
What is 3'-end processing?
The process where pre-mRNA is chopped and a poly(A) tail is added.
220
What is RNA export?
The process of transporting mature mRNA from the nucleus to the cytosol.
221
What is transcription?
The process by which cells read the instructions in their genes.
222
What is an RNA transcript?
The RNA chain produced by transcription, complementary to the template DNA.
223
What is gene expression?
The process of converting DNA information into a functional product.
224
What is RNA capping?
A modification of the 5' end of mRNA involving a guanine nucleotide with a methyl group.
225
What is polyadenylation?
The addition of adenine nucleotides to the 3' end of an RNA transcript.
226
What are introns?
Segments of DNA or RNA that do not code for proteins.
227
What are exons?
Segments of DNA or RNA that contain information coding for a protein.
228
What is RNA splicing?
The process of removing introns and stitching together exons.
229
What is pre-mRNA?
mRNA that has not yet undergone splicing.
230
What is snRNA?
RNA molecules that participate in RNA splicing.
231
What is alternative splicing?
The production of different mRNAs from the same gene by splicing RNA transcripts differently.
232
What are Cajal bodies?
Sites in the nucleus where snRNPs and snRNAs mature.
233
What are interchromatin granule clusters?
Stockpiles of snRNPs and RNA-processing components used in mRNA production.
234
What are nuclear core complexes?
Structures that mediate the transport of mRNA from the nucleus to the cytosol.
235
What is a mutation?
A stable change in the DNA sequence that can be neutral, beneficial, or deleterious.
236
What are point mutations?
Mutations where one coding base is changed, affecting a specific amino acid.
237
What are insertions/deletions?
Mutations where a codon is inserted or deleted, altering the amino acid sequence.
238
What are repetitions in mutations?
Mutations where the number of repetitions of a sequence is changed.
239
What are chromosomal rearrangements?
Mutations where the coding sequence is inverted.
240
What are silent mutations?
Mutations that change a base but do not alter the encoded amino acid.
241
What are nonsense mutations?
Mutations that change a base to encode a stop codon.
242
What are missense mutations?
Mutations that change a base, altering one or more amino acids in the sequence.
243
What is redundancy in genetics?
The existence of multiple codons for one amino acid.
244
What are aminoacyl-tRNA synthetases?
Enzymes that correct mistakes made by tRNA during translation.
245
What is a Silent Mutation?
A mutation in which even though a base changes, the same amino acid is still encoded for.
246
What is a Nonsense Mutation?
A mutation in which a change in the base encodes for a stop codon.
247
What is a Missense Mutation?
A mutation in which a change in the base changes one or more amino acids in the sequence.
248
What is Redundancy in genetics?
Where there exist multiple codons/sequences for one amino acid.
249
What is the role of Aminoacyl-tRNA Synthetases?
Fixes any mistakes made by the tRNA in translation by identifying the tRNA anticodon nucleotides, recognizing the nucleotide sequence of the acceptor stem/arm, and reading nucleotide sequences at additional positions on the tRNA.
250
What is Translation?
The synthesis of polypeptides on ribosomes; small subunit binds to the mRNA and the large subunit has binding sites for the tRNAs and also catalyzes peptide bonds between amino acids.
251
What occurs during Initiation of Translation?
The small ribosomal subunit attaches to the start of the mRNA sequence; the tRNA molecule carrying methionine attaches to the start codon of the mRNA; the large ribosomal subunit joins the complex, forming a functional ribosome.
252
What happens during Elongation of Translation?
The ribosome continues to translate each codon in turn; each corresponding amino acid is added to the growing chain; the amino acids are linked together by peptide bonds.
253
What is Termination in Translation?
The ribosome reaches a stop codon (UAA, UAG, or UGA); the ribosome falls off the mRNA molecule and releases the protein.
254
What is a Ribozyme?
An enzyme that catalyzes translation.
255
What is the function of EF-TU (EF1 in eukaryotes)?
It checks aminoacyl tRNA.
256
What is the role of EF-G (EF2 in eukaryotes)?
Helps the ribosome to move the mRNA forward by one codon and helps speed up the elongation of the polypeptide chain.
257
What is the Shine-Dalgarno Sequence?
A short RNA sequence that helps start protein synthesis in bacteria and archaea, located in the ribosome-binding site of messenger RNA, and helps signal the start of translation.
258
What is a Translation Initiation Factor?
Protein that promotes the proper association of ribosomes with mRNA and is required for the initiation of protein synthesis.
259
What is f-Methionine Aminoacyl tRNA?
A transfer RNA (tRNA) that carries formylmethionine (fMet) to ribosomes to begin protein synthesis.
260
What are Polyribosomes/Polysomes?
Macromolecular complexes made up of multiple ribosomes simultaneously translating a single mRNA into polypeptide chains.
261
What are Ribosomal Proteins?
Are located near the surface and fill in gaps in the RNA; they help to fold and stabilize the RNA core as well monitoring changes to the rRNA.
262
What is Initiator tRNA?
Starts the translation process by carrying over methionine, the amino acid which is always in the start position and is distinct from the tRNA that usually carries methionine.
263
What are Release Factors?
Proteins that end translation by binding to stop codons in a ribosome which releases the new polypeptide from the ribosome.
264
What are Inhibitors in the context of gene expression?
Drugs which inhibit bacterial but not eukaryotic gene expression and are often used as antibiotics to treat illnesses.
265
What is Proteolysis?
The process of breaking down proteins into smaller peptides or amino acids.
266
What are Proteases?
Enzymes which degrade proteins first to short peptides then to individual amino acids by hydrolyzing the peptide bonds between amino acids.
267
What are Proteasomes?
Large protein machines present in the cytosol and nucleus of eukaryotes which help to break down proteins; they contain a cylinder in the middle with stoppers at the end which binds to proteins and using ATP hydrolysis unfold the proteins and move them inside the cylinder.
268
What is Ubiquitin?
Proteins which steer growing polypeptides along productive folding pathways and prevent them from aggregating inside the cell.
269
What is an Anticodon?
A trinucleotide sequence located at one end of a tRNA molecule; is the corresponding codon in a mRNA sequence.
270
What is Antibiotic Resistance?
When bacteria becomes resistant to antibiotics and can be avoided if antibiotics is prescribed for only serious infections, hygiene is prevented and companies develop new types of antibiotics.
271
What are Antibiotics?
Chemotherapeutic agents that inhibit or prevent bacterial growth and they do not work on viruses.
