How can we help?

You can also find more resources in our Help Center.

57 terms

Ch. 4

STUDY
PLAY
A Karyotype shows the ____ chromosomes sorted and isolated from a cell in ___
46, Metaphase
all of the following participate in DNA replication except
ribosomes.
_____ opens up one segment of the DNA helix during replication, whereas ____ adds complementary free nucleotides to the exposed DNA strand.
DNA Helicase; DNA polymerase
A _____ contains the necessary information for the production of a molecule RNA.
gene
G1, S and G2 phases are collectively called
Interphase
all of the following are directly involved in translation except
DNA
Since there are no genes coding for carbohydrates, nucleic acids, or lipids, how do cells produce them?
Enzymes encoded by genes synthesize these products.
DNA polymerase is most active in
S
DNA never migrates from the nucleus to the cytoplasm to participate directly in protein synthesis.
True
Phenotype is the result of genetic influences only
False
The allele for cleft chin (C) is dominant to the allele for uncleft chin (c). A male and female who are both heterozygous for cleft chin have a child. what is the chance that this child will have an uncleft chin?
25%
DNA replication is called semicoservative because
each daughter DNA consists of one new helix and one old helix
Sister chromatids are pulled to opposite poles of a cell during.
anaphase
A ___ is composed of a granular cluster of eight proteins called ____ with DNA wound around them, plus a short segment of linker DNA
nucleosome; histons
all Proteins made by the ribosomes are exported from a cell for use elsewhere in the body.
false
all of the body's nonreproductive cells, called ___, usually have ____ and are thus called _____ cells.
somatic cells; 23 pairs of chromosomes; diploid
although all cells synthesize phospholipids, there are no genes for phospholipids.
true
the stage at which chromosomes aggregate along the equator of a cell is
metaphase
germ cells have ____ upaired chromosomes and are thus called ___ cells.
23; haploid
naked DNA is called chromatin
false
a cell starting prophase has 92 molecules of DNA in its nucleus.
true
the human genome consists of
about 35,000 genes
in familial hypercholesterolemia, individuals with two abnormal alleles die of heart attacks in childhood, those with only one abnormal allele typically die as young adults, and those with two normal alleles have normal life expectancies. this exemplifies.
Incomplete dominance
_____ are turned on of off by regulatory proteins in accordance with changing needs for the ____ they encode.
Genes; proteins
Copying genetic information from DNA into RNA is called _____, whereas usiing the information contained in mRNA to make a polypeptide is called _____.
transcription; translation
the gene for a poly peptide made of 51 amino acids would have a minimum number of
153 bases.
after translation, a protein may undergo structural changes called ____ modifications.
posttranslational
mitosis is responsible for embryonic development and tissue growth.
true
oncogenes and tumor-suppressor genes have similar effects on cell division
false
a cell finishing mitosis has ___ DNA molecules, while a cell finishing DNA replication has ___ DNA molecules
46; 92
after mitosis each chromosome consists of two parallel filaments called sister chromatids.
false
anticodons, codons, and base triplets correspond to ____, respectively
tRNA, mRNA, and DNA
You were able to radioactively tag and thereby trace an amino acid that is used to make insulin, a hormone that will be exported out of the cell. The pathway of the tagged amino acid would be
rough ER ---> golgi complex ---> golgi vesicle --> extracellular fluid.
DNA is a polymer of ____, which consists of a sugar, a phosphate group, and a ____
nucleotides; nitrogenous base
many genes occur in alternative forms called alleles
true
which of these processes occurs during a cell's first gap (g1) phase?
The cell synthesizes proteins and grows.
if one allele is not phenotypically expressed in the presence of another, we say that it is a ___ allele
recessive
all these are found in the karyotype of a normal human male, except
46 chromatids
Hemophilia is caused by a sex-linked recessive allele. this mean that.
a son who has hemophilia inherited the allele from his mother
All the DNA in one 23-chromosome set is called
Genome
Cytokinesis overlaps with which phase of mitosis?
telophase
which of these is the correct sequence from simpler to more complex?
carbon, nitrogenous base, nucleotide, DNA, chromatin
____ is the DNA base sequence complementary to the strand TGCCAT
ACGGTA
there are three codons that do not code for any amino acid
true
chromatin shortens and thickens, coiling into compact rods during
prophase
DNA is composed of double-ring nitrogenous bases, whereas RNA is composed of single-ring nitrogenous bases.
false
which of the following omits some stage of the cell cycle?
prophase, metaphase, anaphase, telophase, cytokinese
eye color is a normal polygenetic trait.
true
if DNA molecule were known to be 22% thymine, what would be the percentage of guanin?
28%
The enzyme RNA polymerase participates in translation
false
the genetic code is the correspondence between the ___ and the ___ that they represent
mRNA codons; 64 amino acids
a mutation is
a change in DNA structure that might be beneficial, harmful, or neutral
Transcription occures in the ____, but most translation occurs in the ___
nucleus; cytoplasm
Cell division is stimulated by ___ and suppressed by ____
growth factors; contact inhibition
all these can cause a mutation except
a mistake made by the RNA polymearse
the alleles possesed by all members of a population collectively are called the
gene pool
a gene can be defined as an information-containing segment of RNA that codes for the production of a polypeptide.
false