Biology Final Exam
Terms in this set (193)
The flow of genetic information-central dogma
Overview of transcription & translation-in PROKARYOTES
In a bacterial cell, mRNA produced by transcription is immediately translated w/o additional processing.
Overview of transcription & translation-in EUKARYOTES
Nucleus provides a separate compartment for transcription. Original RNA transcript called pre mRNA is processed in many ways before leaving the nucleus as mRNA.
3 steps in transcription:
1. Pries the 2 strands on DNA apart
2. Joins together RNA nucleotides complementary to the DNA template strand;
3. Elongates the RNA polynucleotide
4. Assembles a polynucleotide only in its' 5' to 3' direction
Primer is NOT needed for:
Primer IS NEEDED for:
The functioning process for RNA polymerase is..
The functioning process for DNA polymerase is..
location of TATA box:
upstream from the transcription Startpoint
in the eukaryotic promoter region
RNA processing-addition of 5' cap & poly A tail; The modified ends may:
-promote export of mRNA from nucleus;
-help protect mRNA from degradation
-in conjunction with certain cytoplasmic proteins, facilitate ribosome attachment
when mRNA in cytoplasm
where introns are removed
anticodons are written from..
3' to 5'
Concept of Wobble?
the flexible base paring
at the third position of an
Anatomy of a functioning ribosome:
A ribosome has an mRNA binding site and three tRNA binding sites, known as A,P, and E sites.
Name 3 steps in translation:
initiation, elongation and
What is a signal peptide?
a sequence of about 20 amino acids at or near the leading end
(N-terminus) of a polypeptide
What is SRP?
Signal recognition particle, recognizes the signal peptide
2 ways to augment the number
Of copies of a polypeptide:
1. Multiple ribosomes translate an mRNA at the same time;
2. Transcribing multiple mRNAs from the gene
Small Mutations that affect mRNA sequences: Wild Type
(refer to chpt 17 powerpoint)
Function of acetylation of histone tails:
chromatin structure that permits transcription
A eukaryotic gene & its transcripts:
Alternative RNA splicing:
Effects on mRNAs by microRNAs & small interfering RNAs:
1.5% of human genome is composted of protein-coding DNA
In 2012, the entire human genome is sequenced, which revealed that about ____% of the genome is transcribed at Some point in any given cell.
It's suggested that a large amount of the genome is transcribed into non-protein-coding RNAs, aka noncoding RNAs or _____________
2 types of ncRNAs?
large and small
2 types of SMALL RNAs?
siRNAs and miRNAs
-single-stranded RNA molecule of about 22 nucleotides
-capable of binding to complementary sequences in mRNA
-processed from a longer RNA precursor
-forms complex with one or more proteins
expression of at least one-half of all human genes may be regulated by miRNAs
-in turn, the complex either degrades/blocks the target mRNA's translation
Small interfering RNAs (siRNAs) are..
-similar in size and functions to miRNAs
- associate with same proteins, making same results
Difference between miRNAs and siRNAs:
subtle differences in structure of precursors, mostly double-stranded RNA molecules
the blocking of agene expression by siRNAs is called...
RNA interference (RNAi)
Viral replicative cycle
Viruses as intracellular parasites that do what?
hijack cellular machinery
Classes of animal viruses
Also, ss rRNA could serve as template for either ____________________.
mRNA synthesis or DNA synthesis.
-transcribes an RNA
template into DNA
-viruses equipped with
What are retroviruses?
LAB 16 PROTEIN SYNTHESIS
Refers to the transfer of information from DNA in a gene to a product
What is gene expression?
Process of making a RNA strand using a DNA template.
Catalyzed by the enzyme RNA polymerase.
What is transcription?
The process of proteins synthesis
Takes place at the ribosomes
What is translation?
Name 3 types of RNA?
Messenger RNA, Ribosomal RNA, Transfer RNA
3 DIFFERENCES between DNA and RNA?
DNA is double stranded, RNA is single stranded.
DNAs sugar is deoxyribose, RNas sugar is ribose.
RNA has Uracil, DNA has Thymine.
Correlates language of NUCLEIC w the language of proteins.
What does the genetic code do?
A nucleotide triplet in the code, corresponds to one of 20 amino acids.
What is a codon?
There can be more than one codon for each amino acid.
What is a degenerate?
The codon AUG is an initiation codon that begins the synthesis of a protein
What is a START codon?
-three codons, UAG, UGA AND UAA are termination codons that signal the end of an amino acid sequence in a growing polypeptide.
What is a STOP codon?
Coding sequences of a gene.
What are EXONS?
Most of the chromosomal sequences are this
What are INTRONS?
In prokaryotes, there are no __________, and _____________ sequences are interrupted.
there are no introns, and codon sequences are interrupted
In eukaryotes, _________ of a gene are often interrupted by ___________.
EXONS of a gene are often interrupted by INTRONS.
This genome RARELY contains introns.
What is a BAKER'S YEAST'S genome?
This genome DOES NOT contain introns.
What is a MITOCHONDRIAL genome?
The linear sequence of amino acids.
What is a PRIMARY structure?
Has a 2-D structure, alpha helix and beta sheet.
What is a SECONDARY structure?
Hydrophobic amino acids turn toward the core of a globular conformation.
What is a TERTIARY structure?
Proteins composed of two or more polypeptide subunits
What is a QUATERNARY structure?
This is found in red blood cells, is an iron containing protein, functions in H2O transport and delivery, is a tetramer made of 4 polypeptide subunit chains, AND has 2 alpha & 2 beta chains.
What is HEMOGLOBIN?
CHPT 20 RECENT ADVANCES IN DNA RESEARCH AND BIOTECHNOLOGY
2 basic purposes of gene cloning are?
-Make copies of a gene
-Produce protein product
DNA molecule that can carry foreign DNA into a host cell and replicate there.
What is a CLONING VECTOR (PLASMID)?
DNA carries sequences from different sources.
What is RECOMBINANT DNA?
Construction of a plasmid:
What does PCR stand for?
Polymerase Chain Reaction
What are the (4) components needed for a PCR reaction?
What makes Taq DNA polymerase unique?
What are the 4 steps in a PCR reaction?
Denaturation, Annealing, Extension 1 and 2
USE OF A RESTRICTIONENZYME & PCR INGENE CLONING
PCR primers are designed so that the DNA fragments have a ______________ site at each end that matches the one in the cloning vector.
Any cell with the potential to give
rise to all the specialized cell
types of the organism.
What is a TOTIPOTENT?
A stem cell can divide into _________________________ and a ______________________.
into another STEM CELL and a PRECURSOR CELL.
Cells that can generate all embryonic cell types.
What is an EMBRYONIC STEM CELL?
Cells that generate a limited number of cell types.
What is an ADULT STEM CELLS?
Different types of differentiated cells?
Liver, nerve, blood cells.
Turn back the clock in fully differentiated cells, reprogramming them to act like ES cells
What are IPS cells?
Introduction of genes into
an afflicted individual for
What is GENE THERAPY?
LAB: 17 & 18 DNA FINGERPRINTING
Exists in bacteria, recognizes specific DNA sequences, digests DNA by cleaving phosphodiester bonds b/w successive nucleotides.
What are RESTRICTION ENZYMES?
Restriction enzymes are considered ENDONUCLEASES bc they:
BREAK BONDS b/w internal nucleotides within the DNA molecule.
Used by bacteria to destroy the DNA of invading bacteriophages.
What are ENDONUCLEASES?
Application of restriction enzymes:
-sequencing of DNA genomes
-cloning of a gene
Restriction Enzymes: Nomenclature:
-named after the organism it isolated
TYPES OF RESTRICTION ENZYMES
DIFFERENT recognition/cleavage site, TWO enzymes required for recon & cleavage, NO palindromic recog. sequence
SAME recognition/cleavage site, ONE enzyme required for recon & cleavage, has a palindromic recog. sequence
DIFFERENT recognition/cleavage site, ONE enzymes required for recon & cleavage, NO palindromic recog. sequence
the nucleotide sequence reads the same from 5' to 3' in the two
complementary DNA strands.
What is PALINDROMIC?
cutting straight through two complementary bases leaves each new
double-stranded DNA fragment with a blunt end
What is a BLUNT END?
Type II restriction endonucleases make a certain cut, this leaves some nucleotides unpaired on the ends of the new double-stranded DNA pieces
What is a STAGGERED CUT?
The staggered ends of a restriction DNA fragment are also called _____________?
Commonly used in DNA technology, palindromic recon. sequences (reads from 5' to 3'), blunt ends, staggered cut, sticky ends.
What are TYPE II RESTRICTION ENZYMES?
Shows LOCATION of specific restriction recognition sequences within the DNA molecule
Can be generated by digesting a DNA molecule with a given set of restriction endonucleases
What is a RESTRICTION MAP?
Sequence outcome of a restriction enzyme cut (EcoRI)?
To separate DNA fragments of different sizes.
Negatively charged DNA fragments move to a positively charged electrode through a soft gel medium.
What is GEL ELECTROPHORESIS?
Smaller DNA fragments move through a gel FASTER than larger fragments
DNA fragments in gel can be seen by staining DNA with special dye
What is GEL ELECTROPHORESIS?
-there is a(n) _______________ relationship b/w the log of the size of a DNA fragment and the distance traveled by the DNA through the gel matrix
1. log of a fragment size (in bp) vs. distance migrated through the gel
2. Can be used to estimate the sizes of unknown DNA fragments in a gel
What is a STANDARD CURVE?
Slight differences in the DNA of genetic makeup among individuals.
Within the non-coding sequence region.
What is POLYMORPHISM?
What does RFLP stand for?
(Restriction Fragment Length Polymorphism)
What does VNTR stand for?
(variable number tandem repeat) - source for RFLP
What does STR stand for?
(Short tandem repeat)
1. usually 2-6 bp in length
2. around the centromere of a chromosome
What is a STR?
-A person's RFLP pattern
-Can be used for forensic DNA analysis
-Or detect the presence of certain disease-causing genes
What is DNA FINGERPRINTING?
-An individual's DNA
-Cut with specific restriction enzymes
-Southern blotting (DNA bands on agarose gel are denatured & transferred to nylon membrane, then single-stranded DNA probes locate desired genomic DNA sequences among the fragments on membrane)
-Radioactive tag attached to probes will light up on membrane & reveal different pattern for each individual
What is RFLP TECHNOLOGY?
CHPT 14 MENDELIAN GENETICS
Advantages using peas as a model system to study genetics:
-short generation time
-large number of offspring from each mating
-mating can be strictly controlled
Pollen-producing organs, the male fertilizing organ of a flower.
What are STAMENS?
Egg-bearing organ, the female reproductive organ of a flower.
What is the CARPEL?
Pollination between two plants
What is CROSS POLLINATION?
over many generations of self-
pollination, had produced only the
same variety as the parent plant
What is TRUE-BREEDING?
Mating of two true-breeding varieties
What is HYBRIDIZATION?
The true-breeding parents
What is the P GENERATION?
The hybrid offspring of P generation
What is the F1 GENERATION?
The offspring of F1 hybrids to self-pollinate or to cross-pollinate with other F1 hybrids
What is the F2 GENERATION?
Allele that determines the organism's appearance.
What is the DOMINANT ALLELE?
Allele that has NO noticeable effect on organism's appearance.
What is the RECESSIVE ALLELE?
The two alleles for a heritable character segregate during gamete formation and end up in different gametes.
What is the LAW OF SEGREGATION?
An organism has a pair of
identical alleles for a character.
What is HOMOZYGOUS?
An organism has two different
alleles for a gene.
What is HETEROZYGOUS?
An organism's appearance or
What is a PHENOTYPE?
An organism's genetic makeup.
What is a GENOTYPE?
How can we tell the genotype of a given purple flower? Is it a homozygous or heterozygous?
Breeding an organism of unknown genotype with a recessive homozygote
What is TESTCROSS?
The alleles for each gene
segregate independently of
those of the other.
What is the LAW OF INDEPENDENT ASSORTMENT?
To determine the probability that two or
more independent events will occur
together in some specific combination, multiply the probability of one event by
the probability of the other event
What is the MULTIPLICATION RULE?
The probability that any one of two or more
Mutually exclusive events will occur is
Calculated by adding their individual probabilities.
What is the ADDITION RULE?
Offspring always Looked like one of the two parental varieties.
What is COMPLETE DOMINANCE?
Neither allele is dominant over the other.
What is INCOMPLETE DOMINANCE?
An example of a gene existing in more than 2 allelic forms?
ABO Blood type
The phenotypic expression of a
gene at one locus alters that of
a gene at a second locus
What is EPISTASIS?
Many characters vary in the population in gradations along a continuum.
What are QUANTITATIVE CHARACTERS?
An additive effect of two or more genes on a single phenotypic character.
What is POLYGENIC INHERITANCE?
What also plays a role in determining the phenotype
of an organism?
a family tree describing the traits of parents and children across the generations.
What is a PEDIGREE?
Individuals w/ heterozygous
Genotype of a disease
May transmit the
Recessive allele to their
What are CARRIERS?
A genetic disorder w/ evolutionary implications.
What is SICKLE-CELL DISEASE?
About_______ African-Americans have
Sickle-cell trait, an unusually high
Frequency of heterozygotes for an
Allele with severe detrimental effects
Having a single copy of the __________________ reduces the
frequency & severity of malaria attacks.
The branch of biology concerned with the transmission of inherited traits.
What are GENETICS?
A unit of inheritance.
What is a GENE?
A segment of DNA that carries information, usually for making a protein.
What is a LOCUS?
Variable forms of a single gene.
What are ALLELES?
An individual that has two copies of the same allele for a gene.
What is HOMOZYGOUS?
An individual that has two different alleles for a gene.
What is HETEROZYGOUS?
An allele is expressed or seen; either homozygous or heterozygous.
What is DOMINANT?
An allele is only expressed when the individual is homozygous for that allele.
What is RECESSIVE?
Collection of the history of how a genetic trait arose in an individual.
What is PEDIGREE ANALYSIS?
To predict the probability of a genetic trait arising in a future generation.
What is the PUNNETT SQUARE ANALYSIS?
Any chromosome that is not a sex chromosome.
What is an AUTOSOME?
Individuals having 2 X chromosomes are female; individuals having 1 X chromosome 1 Y chromosome are male.
What are SEX CHROMOSOMES?
A display of one's chromosomes according to size and centromere position.
What is a KARYOTYPE?
A gene locus is on an autosome.
What iS AUTOSOMAL INHERITANCE?
A gene locus is on a sex chromosome.
What is SEX-LINKED INHERITANCE?
An abnormal number of chromosomes; can involved either autosomes or sex chromosomes.
What is an ANEUPLOIDY?
Chromosomes fail to separate properly during cell division.
What is NONDISJUNCTION?
One extra copy of a chromosome.
What is a TRISOMY?
A rearrangement of parts of different, nonhomologous chromosomes; can lead to deletion of parts of genes, or fusion between different genes.
What is TRANSLOCATION?
A person's chromosomes are directly observed and analyzed.
What is CYTOGENETIC ANALYSIS?
Frequencies of phenotypes in our population determined how?
by DIVIDING the number of students that have that phenotype by the TOTAL number of students in the class
A chemical substance able to stimulate cell division.
What is a MITOGEN?
A chemical substance able to arrest cells in metaphase of mitosis by freezing the mitotic spindle.
What is a COLCHICINE?
A collection of all the chromosomes in a cell.
What is a CHROMOSOME SPREAD?
Stained chromosomes showing characteristic staining pattern; helps to identify each of the different homologous chromosome pairs.
What is a BANDING PATTERN?
Giemsa stained chromosomes.
What are G-BANDS?
CHP 15 CHROMOSOMES & INHERITANCE
CHROMOSOME BASIS OF MENDEL'S LAWS
Meiosis metaphase I, chromosomes follow the Law of segregation and law of independent assortment.
Known phenotype ----->unknown GENOTYPE
What is FORWARD GENETICS?
Known genotype -----> unknown PHENOTYPE
-an approach to discover the function of a gene by analyzing the phenotypes arisen from the mutations of the gene.
-common in labs
What is REVERSE GENETICS?
The phenotype for a character most commonly observed in natural population.
What is a WILD TYPE?
Traits that are alternatives to the wild type.
What is a MUTANT?
CHROMOSOMAL BASIS of x-linked eye color
The eye color gene
Is located on the
SOME CHROMOSOMAL SYSTEMS OF SEX DETERMINATION:
X-Y SYSTEM, X-0 SYSTEM, Z-W SYSTEM, HAPLOD-DIPLOID SYSTEM
X-linked recessive traits
Color blind father will transmit the mutant allele to all daughters but to no sons
If carrier mates with a male who had normal color vision, there is 50% chance that each daughter will be a carrier like her mom and 50% chance each son will have a disorder.
X-linked recessive traits
If carrier mates w/ color-blind male, there is 50% chance each child will have disorder, REGARDLESS OF SEX. Daughter with normal color vision are carriers, males with normal color vision are FREE of recessive allele.
Almost all of one
X chromosome in each cell
In female mammals become
Inactivated during early
What is X INACTIVATION?
Result of X INACTIVATION?
The cells of
Females and males have
The same effective dose
(one copy) of most X-linked
1. the inactive X in each cell of a female condenses into a
2. most of the genes of the Barr body are not expressed.
3. in the ovaries, Barr-body chromosomes are reactivated in the cells that give rise to eggs, such that following meiosis,
every female gamete (egg) has an active X
BARR BODY CHARACTERISTICS
Genes located near each other on the same chromosome tend to be
Inherited together in genetic crosses; such genes are said to be genetically linked.
What are LINKED GENES?
The production of offspring with combinations of traits that differ from those found in either P generation parent.
What is GENETIC RECOMBINATION?
The offspring inherited a phenotype that matches either of the phenotypes of the P generation
What is the PARENTAL PHENOTYPE?
The offspring have new combinations of phenotypes from the P generation
What are RECOMBINANT TYPES?
Accounts for the recombination of linked genes.
What is CROSSING OVER?
Chromosomal basis for recombination of linked genes
CONSTRUCTING A LINKAGE MAP
Linkage map shows relative locations of genes along a chrom.
Linkage map is based on assumption that the probability of a crossover b/w the two genetic loci is proportional to the distance separating the loci.
Map units are distances b/w genes.
Alternation of chromosome structure
Deletion REMOVES A SEGMENT.
Duplication REPEATS A SEGMENT.
Inversion REVERSES A SEGMENT WITHIN A CHROM.
Translocation MOVES SEGMENT FROM ONE CHROM TO A NONHOMOLOGOUS CHROM.
Variations in phenotype depending on whether an allele is inherited from the male or female parent.
What is GENETIC IMPRINTING?
Are two genes linked or unlinked?-using the chi-square (Χ2) test:
Relating a statistical method assessing the goodness of fit between observed
Values and those expected theoretically.