BSC 2011 UNIT I Practice Exam 1e 1 The majority of genes in an organism s genome code for A tRNA molecules B proteins C carbohydrates D rRNA E none of these 2 The genetic information contained within a gene resides in its A sequence of amino acids B sugar phosphate chain C sequence of ribonucleotide bases D double helix E sequence of deoxyribonucleotide bases 3 In a sea urchin the end result of the cleavage stage of embryonic development is A a gastrula B a neurula C a morula D an archenteron E a blastula 4 What can be said of methylated regions of DNA A genes in these regions are being expressed B genes in these region are being transcribed C genes in these region are being translated D genes in these regions are inactivated E both choices A and B 5 Laboratory tissue culture techniques are used to make several clones from a parental carrot plant Clones that grown in low light conditions produce broad leaves whereas clones that are grown in bright light produce much narrower leaves This is an example of A maternal determination B polyphenism C differential genomic equivalence D morphogenic regulation E genetic induction 6 Which of the following is an example of a maternal cytoplasmic determinant A Drosophila bicoid mRNA D mesodermal N cadherin B tadpole thryroxin E none of the above C ectodermal N cadherin 7 What occurs at a ribosome A transcription of mRNA D transcription of DNA E translation of mRNA B replication of mRNA C translation of tRNA 8 Which process below is NOT involved in cell differentiation A induction B cell signaling C determination D gene regulation E DNA replication 9 How does an adult stem cell ASC differ from an embryonic stem cell ESC A There is no such thing as an adult stem cell B Some genes are irreversibly turned off in an ASC but not in an ESC C An ASC is totipotent an ESC is pluripotent D An ASC doesn t respond to inductive signals whereas an ESC still does E none of the above 10 Differentiated cell types first appear during A organogenesis B cleavage C neurulation D blastulation E gastrulation 11 The blastopore opening is formed in a sea urchin embryo by A cleavage of cells at the animal pole C invagination of surface cells at the vegetal pole B involution of primary mesenchyme cells D involution of the zygote cell membrane E ingression of primary mesenchyme cells 12 13 Which is the correct sequence of events leading to the fast block to polyspermy during sea urchin fertilization A calcium wave cortical reaction fertilzation envelope B cortical reaction membrane depolarization fertilization envelope C acrosomal reaction calcium wave cortical reaction D acrosomal reaction sperm egg protein recognition membrane depolarization E fusion of gamete cell membranes acrosomal reaction fertilization envelope 14 Which of the following is true with respect to cells in the dorsal lip of the blastopore in amphibian embryos A They induce the subsequent development of neural ectoderm B They contain cytoplasmic determinants from the gray crescent of the zygote C They induce the development of subsequent dorsal features of the embryo D choices A and B only E choices A B and C C be unable to develop a dorsal ventral axis 15 A researcher creates a Drosophila mutant in which the bicoid gene is knocked out i e irreversibly inactivated The mutated embryo that results will A express bicoid uniformly in all of its cells D be unable to develop anterior head structures E develop head structures at both its anterior and posterior ends 16 17 Holtfretter s experiment during which he caused the cells of a frog late gastrula to dissociate provided evidence that A cells can communicate B cells selectively adhere to similarly differentiated cells cells of the same type D choices A and B only C cells of one type selectively adhere to a different type of cell B be unable to develop posterior tail structures E choices A B and C 18 Which sequence correctly represents the hierarchy of developmental gene expression A Hox genes segmentation genes maternal effect genes B segmentation genes Hox genes maternal effect genes C Hox genes maternal effect genes segmentation genes D maternal effect genes Hox genes segmentation genes E maternal effect genes segmentation genes Hox genes 19 The notocord of vertebrates is derived from what type of germ tissue A neural ectoderm B neural endoderm C mesoderm D choices A and B E choices A and C 20 Which of the following directly play a role in cell cell recognition during embryonic development A Hox genes B cadherins C cortical granules D cytoplasmic determinants E all of the above 21 How does a protein called a morphogen act to direct the proper spatial organization of embryonic structures A The presence or absence of the morphogen in a cell determines which genes are expressed or not B Cells containing different concentrations of a morphogen will express different sets of genes C The presence of a morphogen in a cell will cause cell death D The absence of a morphogen will cause cell death E The presence of a morphogen initiates cell division 22 Which type of gene is most directly responsible for the different body plans observed in different animals such as insects and crustaceans A maternal effect genes B bindin coding genes C bicoid coding genes E all of the above D Hox genes 23 Which of the following pairs of cell types are genomically equivalent A Mary s skin cell a skin cell from Mary s mother C Mary s skin cell Mary s pancreatic cell B Mary s skin cell Mary s egg cell D Mary s skin cell a skin cell from her sister 24 Which is true of hormones such as testosterone and thyroxin A a particular hormone targets one particular type of cell or tissue B a particular hormone can affect gene regulation in multiple types of tissues C hormones take part in signal transduction pathways D hormone signals from one cell induce changes in adjacent neighboring cells E all of the above 25 In vertebrates the zone of polarizing activity is responsible for A directing the proper anterior posterior arrangement of limb bones B directing the proper location of neural tube formation C directing the proper location of invagination during early gastrulation D directing the proper proximal distal arrangement of limb bones E directing the proper anterior posterior body axis of the embryo 26 Features of the nervous system in vertebrates are derived from what type of embryonic germ tissue A gastroderm B blastoderm C ectoderm D endoderm E mesoderm 27 The archenteron is a feature
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