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173 terms

BIO 2: Genes

MCAT
STUDY
PLAY
gene
Series of DNA nucelotides that codes for the production of a single polypeptide, mRNA, rRNA, or tRNA.
euchromatin
Eukaryotic genes that are actively being transcribed are found in ____.
26, 38
There are __ to __ genes found in the human genome.
Central Dogma of genes
DNA -> RNA -> Protein: What is this theory called?
adenine, cytosine
The purines of DNA?
guanosine, thymine
The pyrimidines of DNA?
2
Purines are ___-ringed structures
1
Pyrimidines are ___-ringed structures.
phosphodiester bond, sugar-phosphate backbone
Each nucleotide is bound by a ___ between the 3rd carbon of a deoxyribose and a 5th carbon on the other. This creates the ___.
base pairing
What the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called.
complementary strand
Strands that match so that they can bind to make DNA.
adenine, thymine
2 hydrogen bonds between them.
cytosine, guanine
3 hydrogen bonds between them.
semi-conservative
DNA replication is ____ because it has an old strand and a newly-crafted strand on it.
middle
DNA synthesizing starts in the ___ of a strand.
leading, lagging
DNA has these two strands when being synthesized
DNA polymerase
An enzyme that helps` catalyze in the polymerization of deoxyribonucleotides into a DNA strand. Requires an RNA polymerase to get started.
Okazaki fragment
Short molecules of single-stranded DNA that are formed on the lagging strand during DNA replication.
DNA helicase
Unwinds the DNA.
deoxy
Means it has fewer oxygens somewhere.
DNA ligase
Moves along the lagging strand and and ties the Okazaki fragments together.
RNA primer
DNA polymerase requires a ____ to get started.
First
__ step of DNA replication: Helicase unwinds double helix
second
__ step of DNA replication: RNA polymerase builds a primer.
third
__ step of DNA replication: DNA polymerase asembles the leading and lagging strands.
fourth
__ step of DNA replication: The primers are removed.
fifth
__ step of DNA replication: Okazaki fragments are joined.
telomere
Repeated nucleotide units that protect the chromosomes from being eroded through repeated rounds of replication.
telomerase
It catalyzes the lengthening of telomeres.
ribose
RNA is made from ___.
1
RNA has how many strands?
replication
DNA is produced by ___.
transcription
RNA is produced by ____.
mRNA, rRna, tRNA
The three types of RNA?
messenger RNA
Delivers the DNA code for amino acids to the cytosol where the proteins are made.
ribosomal RNA
This combines with proteins to make ribosomes.
ribosome
These complexes direct the synthesis of DNA.
transfer RNA
Collects amino acids in the cytosol and transfers them to ribosomes so that the ribosomes can make proteins.
nucleolus
Where rRNA is made.
ribonucleic acid
RNA is an abbreviation for?
transcription
Initiation, elongation, termination are the processes that make what?
transcription
The process where RNA is made from a DNA template.
first
___ step of transcription: initiation
second
___ step of transcription: elongation
third
___ step of transcription: termination
RNA polymerase
Is necessary for constructing RNA chains using DNA genes as templates.
promoter
Sequence of DNA nucleotides that designates a beginning point for transcription.
initiation
In ____, RNA polymerase scands the DNA molecule for the promoter.
elongation
In ____, RNA polymerase recognizes the promoter and transcribes the RNA.
termination
In ___, a termination sequence and special proteins help to dissociate RNA polymerase from DNA.
antisense strand (-)
The strand of dna which is not used during transcription to make mRNA. (Template strand)
sense strand (+)
The strand of dNA which is used during transcription to make mRNA. (Coding strand)
activator
Activate the activity of RNA polymerase.
repressor
Stop the activity of RNA polymerase.
prokaryotes
In (eukaryotes/prokaryotes), a change in environment causes a change in genes.
polycistronic
Prokaryotes have ____ mRNA which has many genes in a single transcript.
monocistronic
Eukaryotes have ____ mRNA which has one gene in a single transcript.
operon
A group of genes or a segment of DNA that functions as a single transcription unit. It is comprised of an operator, a promoter, and one or more structural genes that are transcribed into one polycistronic mRNA.
lac operon
Group of adjacent and coordinately controlled genes concerned with the metabolism of lactose in E. Coli.
primary transcript
RNA transcript immediately after transcription in the nucleus, before rNA splicing or polyadenylation to form the mature mRNA.
5' cap
This cap is the attachment site during protein synthesis.
poly A tail
The 3' cap has a ___ which has only adenine bases and protects mRNA from degeneration.
polyadenylation
_____ is the addition of a poly(A) tail to an RNA molecule.
intron
Non-coding, intervening sequences of dna that are transcribed, but are removed from within the primary gene transcript and rapidly degraded during maturation of messenger rna.
exon
The protein-coding region in the DNA.
snRNP (small nuclear ribonucleoprotein)
They join together with proteins to make a spliceosome that loop the exons together so that they can be removed.
introns
Are there more introns or exons?
denature DNA
To ____ means to separate the two strands of DNA's double helix.
G/C
G/C or A/T bands have a higher melting point.
nucelic acid hybridization
This is why you can take some known DNA and unknown DNA and see if they go together to see if they are the same thing.
methylation
Bacteria protect their own DNA with this process, which involves adding -CH3.
restriction enzymes
An enzyme that catalyzes the cleavage of DNA at restriction sites, producing small fragments used for gene splicing in recombinant DNA technology and for chromosome mapping.
palindromic
Can be read the same way either frontwards or backwards.
recombinant DNA
Spliced DNA formed from two or more different sources that have been cleaved by restriction enzymes and joined by ligases.
vector
An organism or vehicle that transmits a piece of genetic material into a host.
plasmid
An organism or vehicle that transmits the causative agent or disease-causing organism from the reservoir to the host.
clone
Genetically identical organism copies.
library
A collection of dna molecules, derived from restriction fragments that have been cloned in vectors, that includes all or part of the genetic material of an organism.
yes
Should libraries be screened for appropriate clones?
lacZ
Some bacteria don't have vectors and some vectors don't have the needed DNA fragment, so include ____ and an antibiotic resistant gene to search for the right bacteria.
probe
A general term for a piece of DNA or RNA corresponding to a gene or sequence of interest, that has been labelled either radioactively or with some other detectable molecule.
cDNA
_____ is reverse transcribed DNA. Lacks introns.
polymerase chain reaction (PCR)
The first practical system for in vitro amplification of DNA and as such one of the most important recent developments in molecular biology.
anneal
The pairing of complementary dna or rna sequences, via hydrogenbonding, to form a double-stranded molecule. Mostoften used to describe the binding of a short primer or probe.`
southern blot
A technique used for searching for a specific dNA fragment.
1. separate DNA fragments by gel electrophoresis

2. Change pH of gel to basic, thus allowing disruption of H-bonds

3. blot gel with nitrocellulose paper

4. Heat paper so as to fix dNA fragments

5. probe with labelled messenger RNA or cDNA

6. wash

complementary mRNA/cDNA fragments will have hybridised.
northern blot
Just like southern blot, but looks for RNA fragments.
RFLP (restriction fragment length polymorphisms)
Used to ID criminals in court cases, based on finding an individual's specific restriction sites in their DNA.
genetic code
Turns DNA nucleotide sequences into amino acid sequences, which later becomes a protein.
degenerative
When more than one series of three nucelotides can code for any amino acid.
unambiguous
When only one code can code for one amino acid.
almost universal
The genetic code is ____, which means almost all living things use the same codes for the same proteins.
codon
Three consecutive nucleotides on a strand of mRNA.
UAA, UGA, UAG
The stop codons.
AUG
The start codon, also codes for amino acid methionine.
20^100
A polypeptide contains 100 amino acids. How many possible amino acid sequences are there for this polypeptide?
3 nucleotide bases
Need what to make an amino acid?
translation
The process of protein synthesis directed by mRNA.
mRNA
Thsi carries the genetic code from the nucleus to the cytosol in the form of codons.
anticodon
A sequence of three adjacent nucleotides located on one end of transfer RNA. It binds to the complementary coding triplet of nucleotides in messenger RNA during translation phase of protein synthesis.
large subunit, small subunit
Things that the ribosome are made of, besides tRNA and proteins.
Svedberg units (S)
The ribosome and its subunits are measured in terms of sedimentation coefficients given in ___.
sedimentation coefficient
Gives the speed of a particle in a centrifuge and is proportional to mass, and related to shape and density.
70
Prokaryotic ribosomes are size __S.
80
Eukaryotic ribosomes are size __S.
no
Sediment coefficients don't add up like normal numbers.
P-site (peptidyl)
X
E-site
Exit site during translation.
A-site
X
translocation
When one piece of random DNA is inserted into another.
deletion
When a portion breaks off during cross-over, homologous recombination, or if it breaks off randomly.
duplication
When a spare fragment breaks off and ends up as an extra in another piece of DNA.
inversion
When the orientation of a piece of genetic code is put on backwards.
transposable elements (transposons)
They can remove themselves from a chromosome and place themselves somewhere else.
nonsense mutation
When a cell makes a stop codon by accident with a mistake insertion or deletion.
forward mutation
Mutation that changes the organism even more.
backward mutation
Fixes the mutation, reverting the area back to normal.
wild type
Genetic code in its original, unaltered form.
tumor
Mass of cancer cells.
oncogenes
Genes that cause cancer.
proto-oncogenes
Genes that stimulate growth.
carcinogens
Mutagens that cause cancer.
frameshift mutation
Mutation with 3 nucleotides changed.
histone
Proteins that dna tightly coils around to form chromosomes.
nucleosome
Contains eight histone molecules, and wrap into coils called solenoids.
chromatin
A complex of nucleic acids (e.g. DNA or RNA) and proteins (histones), which condenses to form a chromosome during cell division.
nucleus, mitochondria
Where is DNA found in inside of animals? (Think of cells.)
chromosome
A structure within the cell that bears the genetic material as a threadlike linear strand of DNA bonded to various proteins in the nucleus of eukaryotic cells, or as a circular strand of DNA (or RNA in some viruses) in the cytoplasm of prokaryotes and in the mitochondrion and chloroplast of certain eukaryotes.
trait
A qualitative characteristic. It is an attribute of phenotype, not of genotype.
homologue
A chromosome that is similar in physical attributes and genetic information to another chromosome with which it pairs during meiosis. A member of homologous chromosome.
diploid
A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father. In a diploid state the haploid number is doubled, thus, this condition is also known as 2n.
haploid
A cell or an organism having half of the number of chromosomes in somatic cells.
life cycle of a cell
G1, S, G2, M, C.
G1 stage
The growth phase in the life cycle of a cell.
G1 stage
Usually the longest stage, its when the cell grows.
G0 stage
A nongrowing stage that many cells in the body stay in.
S stage
The cell cycle devotes itself to replicating DNA here. It now has two sister chromatids.
chromatid
The two strands joined together by a single centromere, formed from the duplication of the chromosome during the early stages of cell division and then separate to become individual chromosomes during the late stages of cell division.
G2 stage
When the cell prepares to divide in the cell life cycle.
mitosis
Nuclear division without genetic change.
stages of mitosis
Prophase, metaphase, anaphase, and telophase.
prophase
Mitosis stage: Condensation of chromatin into chromosomes. Centrioles move to opposite ends of the cell and the spindle apparatus begins to form.
centriole
A self-replicating, small, fibrous, cylindrical-shaped organelle, typically located in the cytoplasm near the nucleus in cells of most animals. It is involved in the process of nuclear division.
spindle apparatus
Any of a network of filaments that collectively form a mitotic spindle (in mitosis) and meiotic spindle (in meiosis). It is chiefly involved in moving and segregating the chromosomes during nuclear division.
aster
A star-shaped cluster of microtubules radiating from the edges of a cell, and seen immediately before and during mitosis of an animal cell.
centromere
The constricted region joining the two sister chromatids that make up an X-shaped chromosome.
kinetochore
A specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape.
metaphase
Mitosis stage: Chromosomes align along the equator of the cell.
anaphase
When sister chromatids split at their attaching centromeres and move towards opposite ends of the cells.
telophase
The cell separates.
cytokinesis
The division of the cytoplasm and the plasma membrane following the division of the nucleus resulting into two cells, each having its own nucleus and cytoplasm surrounded by a plasma membrane.
disjunction
The normal separation or moving apart of chromosomes toward opposite poles of the cell during cell division.
meiosis
A double nuclear division that results in four haploid gametes.
gametes
A mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
germ cell
The reproductive cells in multicellular organisms.
spermatogonium
An undifferentiated male germ cell in the male gonads that divides mitotically, and later develops into spermatocyte.
oogonium
An immature female reproductive cell that gives rise to primary oocytes by mitosis.
spermatocyte
A male gametocyte derived from a spermatogonium, and gives rise to haploid spermatids through meiosis.
oocyte
A female gametocyte.
2
Meiosis has how many rounds of division?
prophase I
Meiosis stage: Homologous chromosomes like up. Crossing over occurs. Has four total chromosomes.
crossing over
A process occurring during meiosis wherein two chromosomes pair up and exchange segments of their genetic material.
genetic recombination
The process of forming new allelic combination in offspring by exchanges between genetic materials (as exchange of DNA sequences between DNA molecules).
tetrad
A group of four closely associated chromatids of a homologous pair.
chiasma
ChiasmaThe point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over like the letter X.
linked
Genes that are close together and are more likely to be inherited together.
alleles
One member of a pair (or any of the series) of genes occupying a specific spot on a chromosome (called locus) that controls the same trait.
metaphase I
Meiosis: Homologues stay attached, start to move to center to line up like an equator.
anaphase I
Meiosis: Separates homologues from their partners.
telophase I
Meiosis: The cell splits apart.
reduction division
Cell division that produces reproductive cells in sexually reproducing organisms.
polar body
The cell that results from the asymmetric division of an oocyte.
II
Is it Meiosis I or II that looks like mitosis?
nondisjunction
The failure of homologous chromosomes to segregate or to separate during and after meiosis.