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Biology Quiz 7

quiz 7 Questions and Answers

At the time the of implantation, the human embryo is called ________. Blastocyst
Which of the following is (are) involved in embryonic development? All of the answers are correct; cell division, cell differentiation, and morphogenesis
Eukaryotic cells control gene expression by which of the following mechanisms? All of the answers are correct; DNA methylation, histones acetylation, nucleosomes, and enzyme modification of chromatin structure
Changes in the shape of the cell usually involves the reorganization of the ________. Cytoskeleton
The embryonic precursor to the human spinal cord is the ______. Neutral tube
For a repressible operon to be transcribed, which of the following must be true? RNA polymerase must bind to the promoter and the repressor must be inactive
Which of the following events is (are) nessicary for the production of a malignant tumor? Both activation of an oncogene in the cell and the inactivation of tumor-suppressor genes with the cells
Transcription of the structural genes in an inducible operon ________. Starts when the pathway's substrate is present
A(n) ________ can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA. Repressor
The outer-to-inner sequence of tissue layers in post-gastrulation vertebrate embryo is _______. Ectoderm - mesoderm - endoderm
Which of the following correctly displays the sequence of developmental milestones? Cleavage - morula - blastula - gastula
Genomic imprinting, DNA methylation,and histone acetylation are all examples of ______. Epigenetic inheritance
In a nucleosome,what is the DNA wrapped around? Histones
The earliest developmental stage among these choices is ________. Morula
The tryptophan operon is a repressible operon that is ________. Turned off whenever tryptophan is added to the growth medium
What is the term for the physical processes that give rise to the shape of an organism? Morphogenesis
As an embryo develops, new cells are produced as a result of ________. Cell division
Animal cells that are present only for a brief developmental phase will, following completion of that phase, undergo _______. Apotosis
From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? Cleavage - gasturlation - organogenesis
A human zygote undergoes its first cell division _______. 24 hours after fertilization
A(n) _______ is a site in the DNA located near the end of the final exon, encoding an RNA sequence that determines the 3’ end of the transcript. Terminator
In mammalian eggs, the receptors for sperm are found in the _______. Zona pellucid
Contact of a sperm with signal molecules in the coat of an eg cause the sperm to undergo _____. The acrosomal reaction
. Uterine implantation due to enzymatic digestion of the endometrium is initiated by the _____. Trophoblast
In humans, identical twins are possible because ________. The gray crescent divides the dorsal-ventral axis into new cells.
To meet a zygote’s metabolic and developmental requirements ___________. Maternal RNA and maternal proteins must be present.
Fertilization normally __________. reinstates diploidy
Cells move to new positions as an embryo establishes its three germ tissue layers during _______. Gastrulation
A(n) _______ binds to a site in the DNA far from the promoter to stimulate transcription. The longer we live, the more mutations accumulate
An open space within the gastrula is the ________. Archenteron
During fertilization, the acrosomal contents _______. Digest the protective jelly coat on the surface of the egg.
Gases are exchanged in the mammalian embryo in the _______. Chorion
The cortical reaction functions directly in the _______. Formation of a fertilization envelope.
Created by: allichandler