BIOL 1201 Exam 3

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snRNPs

"snurps"; small nuclear ribonucleus-proteins

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

0

When PPYY individuals breeds with ppyy individual, and p and y are unlinked, what proportion of the next generation is ppyy?

0%

Gametes possess how many copies of unique chromosomes?

1

With linked genes M and N, what proportion of the cross MMNN x mmnn will be MmNn (without any crossing over)?

1

3 reasons Mendel worked with peas

1. simple, obvious characters (seed shape and color) 2. different traits for each character(round/wrinkled) 3. no blending occurs

Crossing a GgHhJj individual with a GgHhJj individuals (assuming independent assortment and no crossing over) would yield what proportion of GgHhJJ offspring? A) 1/32

1/16

When PpYY individuals interbreed, and there is independent assortment, what proportion of the next generation is PpYY?

1/2

With sex linkage, what proportion of a female dd crossing with a male Dy will have the D phenotype (dominant)?

1/2

Crossing Rr x Rr yields what proportion of rr offspring?

1/4

Crossing XxYy with XxYy with independent assortment yields what proportion of XxYy offspring?

1/4

When PpYy individuals interbreed, and there is independent assortment, what proportion of the next generation is Ppyy?

1/8

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

100%

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G2?

16; 16

Initiation

1st part of transcription; RNA polymerase binds to promoter and opens the double helix

A diploid cell has how many copies of unique chromosomes?

2

Elongation

2nd part of transcription; RNA polymerase adds nucleotides to complement the DNA template

A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

3' UCA 5'.

When YyRr individuals interbreed, and there is independent assortment, what proportion of the next generation is green and round?

3/16

What will be the ratio of eye-color in the F2 generation of these flies?

3:1

Termination

3rd part of transcription; RNA polymerase separates from DNA

If humans have 23 unique chromosomes, how many chromosomes does a human liver cell have?

46

The phosphate group is connected to which position on the deoxyribose?

5'

An Okazaki fragment has which of the following arrangements?

5' RNA nucleotides, DNA nucleotides 3'

TATA box

A DNA sequence in eukaryotic promoters crucial in forming the transcription initiation complex

Chromosome

A cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very long DNA molecule and associated proteins

Mutation

A change in the nucleotide sequence of an organism's DNA

In mitosis, there are chromosomes and chromatids. What is a chromatid?

A copy of a chromosome

Domain

A discrete structural and functional region of a protein

Gene

A discrete unit of heriditary information consisting of a specific nucleotide sequence in DNA

Polyribosome

A group of several ribosomes attached to, and translating, the same mRNA molecule

Splicesome

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons

DNA Ligase

A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3' end of one DNA fragment to the 5' end of another DNA fragment

Introns

A non-coding, intervening sequence within a primary transcript

Anticodon

A nucleotide triplet at one end of a tRNA molecule that base-pairs with a particular complementary codon on an mRNA molecule

The expression of DNA or RNA is controlled by factors. What is a factor?

A protein that attaches to DNA or RNA and helps

Transcription factor

A regulatory protein that binds to DNA and affects transcription of specific genes

Exons

A sequence within a primary transcript that remains in the RNA after RNA processing

What's a general term used by geneticist for a brain or muscle cell?

A somatic cell

Locus

A specific place along the length of a chromosome where a given gene is located

Epistasis

A type gene interaction in which the phenotype expression of one gene alters that of another independently inherited genes

mRNA

A type of RNA, synthesized using a DNA template, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein

Mendel's hypothesis of inheritance

ALternative forms of genes, dominant/recessive genes, one gene from each parent, two alleles for each character separate during gamete production

RNA splicing

After RNA synthesis of a eukaryotic primary RNA transcript, the removal of portions of the transcript (introns) that will not be included in the mRNA and the joining together of the remaining portions (exons)

tRNA

An RNA molecule that functions as a translator between nucleic acid and protein languages by carrying specific amino acids to the ribosome, where they recognize the appropriate codons in the mRNA.

DNA Polymerase

An enzyme that catalyzes the elongation of new DNA by the addition of nucleotides to the 3' end and end of an existing chain.

Primase

An enzyme that joins RNA nucleotides to make a primer during DNA replication, using the parental DNA as a template

Helicase

An enzyme that untwists the double helix of DNA at replication forks, separating the two strands and making them available as template strands

Character

An observable heritable feature that may vary among individuals (color)

Allele

Any of the alternative versions of a gene that may produce distinguishable phenotype effects

How are genetic data encoded in DNA?

By the sequence of the nucelotides

tRNA does what?

Carries amino acids to the ribosomes-mRNA complex

Point mutation

Caused by a single nucleotide substitution resulting in an amino acid substitution

When Mendel coded purple flowers and white flowers, what were the characters and traits?

Character= color; Trait= purple or white

During anaphase of mitosis, human cells have 92 chromosome. How can that be?

Chromatids separate and form discrete chromosomes in anaphase

Recombination between linked genes comes about for what reason?

Crossovers between these genes result in chromosomal exchange.

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?

DNA contains phosphorus, but protein does not.

Transcription occurs in the nucleus?

Depends on the organism

The role of chromosomes in genetic inheritance was realized at the beginning of the 20th Century because of the fusion of what two events.

Development of cytology and discovery of Mendel's work

Which of the following is true of a species that has a chromosome number of 2n = 16?

Each cell has eight homologous pairs.

Heterologous chromosomes carry the same genes? T/F

False

Zygotes are haploid? T/F

False

Mendel's characters and traits are analogous to what?

Genes and alleles, respectively

Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells?

Golgi-derived vesicles

Heterozygous

Having two different alleles for a given gene

Homozygous

Having two identical alleles for a given gene

Sex determination

Humans: XX- female XY- male Insects: XX-female XO- male Birds/fish: ZW- female ZZ- male Bees/ants: Diploid- female Haploid- male

What kind of bonds hold the two strands of DNA together in the double helix?

Hydrogen

What is removed when pre-RNA is converted to mRNA?

Introns

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?

It has half the amount of DNA as the cell that began meiosis.

What is the heterogametic sex in humans.

Male

Differences between Mitosis and Meiosis

Mitosis: duplicated chromosomes with sister chromatids, chromosomes align on metaphase plate, two 2n daughter cells Meiosis: tetrads formed (crossing over), tetrads align on metaphase plate, four 1n daughter cells

In his transformation experiments, what did Griffith observe?

Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

Independent Assortment

Occurs during metaphase I; homologous chromosomes aligning on different sides of the metaphase plate

Crossing over

Occurs during prophase I; when tetrads are formed, some of the DNA from each chromosome is exchanged

A site

One of a ribosome's three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain

E site

One of a ribosome's three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome

P site

One of a ribosome's three binding sites for tRNA during translation. The P site holds the tRNA carrying the growing polypeptide chain

Trait

One of two or more detectable variants in a genetic character (purple/ white)

Why did the F1 offspring of Mendel's classic pea cross (PP x pp) always look like one of the two parental varieties?

One phenotype was completely dominant over another.

Why does an organism's liver cell have 2 copies of each chromosome?

One set is inherited from the organism's mother, and one from its father

34. When Pp individuals interbreed, what are the genotypes of the gametes?

P and p

What is the first product of transcription in eukaryotes?

Pre-RNA

What is transcription?

Production of RNA and DNA

What is translation?

Production of polypeptides from an mRNA template

Why does the DNA double helix have a uniform diameter?

Purines pair with pyrimidines.

If "P" codes for purple flowers, and "p" codes for white flowers, what is the phenotype of a "Pp"?

Purple

All of these are enzymes employed in DNA replication except?

RNA Polymerase

Which enzyme produces the most transcript in transcription?

RNA Polymerase

Which of the following is true for both prokaryotic and eukaryotic gene expression?

RNA polymerase binds to the promoter region to begin transcription.

In which of the following actions does RNA polymerase differ from DNA polymerase?

RNA polymerase can initiate RNA synthesis, but DNA polymerase requires an RNA primer to initiate DNA synthesis.

Independent assortment refers to?

Random mixing of heterologous chromosomes in meiosis

In this test cross of a fruitfly with a sex-linked white eye mutation, what will the F1 offspring look like?

Red eyed

Mendelian segregation of alleles results from?

Separation of homologous chromosomes in meiosis

Chiasmata

The X shaped, microscopically visible region where crossing over has occurred earlier in Prophase I between homologous non-sister chromatids

Pleiotrophy

The ability of a single gene to have multiple effects

A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G2?

The chromosomes would coil and shorten but have no spindle to which to attach.

Chromatin

The complex of DNA and proteins that make up eukaryotic chromosomes.

G1 phase

The first growth phase of the cell cycle, consisting of the proportion of interphase before DNA synthesis begins

DNA Replication

The process in which a DNA molecule is copied; also called DNA synthesis

Centromere

The region on each sister chromatid where they are most closely attached to each other by proteins that bind to specific DNA sequences; this close attachment causes a constriction in the condensed chromosome

Genetics

The scientific study of heredity and heredity variation

G2 phase

The second growth phase of the cell cycle, consisting of the proportion of interphase after DNA synthesis occurs

Incomplete dominance

The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for each other

Independent assortment of chromosomes occurs

The statement is true for meiosis I only.

Chromatids are separated from each other.

The statement is true for mitosis and meiosis II.

Transcription

The synthesis of RNA using a DNA template

Translation

The synthesis of a polypeptide using genetic info encoded in an mRNA molecule. There is a change of "language" from nucleotides to amino acids.

S phase

The synthesis phase of the cell cycle; the proportion of interphase during which DNA is replicated

Heredity

The transmission of traits from one generation to the next

In a two gene cross (a dihybrid cross), what do offspring frequencies of 50% parentals and 50% recombinants indicate?

The two genes are likely to be located on different chromosomes.

What happens to the gametes after they are produced?

They join with other gametes in reproduction or do nothing

In the double helix of DNA, Adenine is always opposite?

Thymine

What is the purpose of mitosis?

To make daughter cells exactly like the parent cells

What is the purpose of DNA replication?

To make more DNA for cell division

What is the purpose of Meiosis?

To make sex cells

Why is there sex?

To mix up genes (proximate)/ to create different types of individuals in population (ultimate)

Translation occurs in the cytoplasm? T/F

True

sister chromatids

Two copies of a duplicated chromosome attached to each other by proteins at the centromere and sometimes at the arms. While joined, two sister chromatids make up one chromosome. Chromatids are eventually separated during mitosis or meiosis II

Mendel's second law of independent assortment has its basis in which of the following events of meiosis I?

alignment of tetrads at the equator

During which phase of mitosis do the chromatids become chromosomes?

anaphase

Heterologous

different chromosomes carrying different genes

An individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?

different possible alignments of chromosomes

Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes

excision of introns.

Ribosomes

functions as the site of protein synthesis; has alarge and small subunit

What are polyribosomes?

groups of ribosomes reading a single mRNA simultaneously

Tetrads

homologous chromosomes pair creating tetrads in prophase I

The human X and Y chromosomes

include genes that determine an individual's sex.

Random Fertilization

millions of different combinations of sperm and egg

Hydra

multicellular asexual organism

X inactivation

only one of the X chromosomes in females are active, the other is inactivated during early development

When we see chiasmata under a microscope, that lets us know which of the following has occurred?

prophase I of meiosis

At which phase are centrioles beginning to move apart in animal cells?

prophase-prometaphase

Missense mutation

results in a protein in which one amino acid is substituted for another

Nonsense mutation

results in a stop codon, which causes traslation to stop

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?

sequence of bases

Polygeny

several genes control a single character (skin pigmentation)

Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

several transcription factors

Human cells have autosomes and...

sex chromosomes

The process of translation, whether in prokaryotes or eukaryotes, requires mRNA, amino acids, ribosomal subunits, and which of the following?

tRNA

Prophase 1 in meiosis differs from prophase in mitosis by the existence of...

tetrads

The strands that make up DNA are antiparallel. This means that

the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand

Chargaff's analysis of the relative base composition of DNA was significant because he was able to show that

the amount of A is always equivalent to T, and C to G.

Which of the following defines a genome?

the complete set of an organism's genes

Homologous

the same kind of chromosome, carrying the same genes

Why do chromosomes coil during mitosis?

to allow the chromosomes to move without becoming entangled and breaking

Particulate theory

traits are inherited as "particles", offspring receive a "particle" from each parent.

Mendel's law of segregation

you get these alleles going to different gametes which occurs in Anaphase I

When Pp individuals interbreed, what proportions of genotypes occur in the next generation?

¼ PP, ½ Pp, ¼ pp


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