Biology Study Guide Test 1 How is development controlled Zygote Transcription mRNA Translation Ribosomes Transcription translation in prokaryotes vs eukaryotes RNA polymerase Promoter Transcription factors Codons Operator Operon Terminator Transcription initiation complex TATA box Trp operon Repressor Regulatory gene Trp repressor Corepressor Repressible operon Cell division cell differentiation Single cell fertilized egg Synthesis of RNA from DNA Carries genetic message from DNA to the protein synthesizing machinery of the cell Synthesis of polypeptide using the information in the mRNA RNA to Protein Site of translation Transcription and translation in prokaryotes are both in the cell no processing of the mRNA while in eukaryotes transcription and rna processing are in the nucleus while translation are outside the cell Pries DNA open and copies DNA in the 5 to 3 direction DNA sequence where RNA polymerase attaches and initiates transcription in prokaryotes it binds directly In eukaryotes a collection of proteins that mediate the binding of rna polymerase and the initiation of transcription A triplet code for amino acids Switch that turns genes on off Positioned within the promoter controls the access of rna polymerase to the genes Operator the promoter and the genes they control the operon In prokaryotes the sequence that terminates transcription The whole complex of transcription factors and RNA poly bound to the promoter Sequence that forms the initiation of transcription in eukaryotes Usually turned on RNA poly can bind to the promoter and transcribe the genes of the operon Can be turned off by trp repressor Binds to operator and blocks attachment of rna poly to the promoter therefore preventing transcription Expressed continuously at a low rate Inactive form with little affinity for operator if tryptophan binds to trp repressor at allosteric site it can change it to active form and turn off operon Cooperates with repressor to turn off operon Ex tryptophan trp because it is on but can be repressed turned off when tryptophan binds to repressor to turn off operon Inducible operon Lac operon Inducer Negative gene regulation Positive gene regulation Histone acetlyation Fertilization Process of fertilization Acromosomal reaction Depolarization Cortical reaction Polyspermy Activation of egg results from Cleavage Operon is off but can be stimulated induced when a molecule interacts with a regulatory protein lac operon Lac repressor is active on its own so gene transcription is usually off Inactivated repressor to turn on transcription Lac trp are examples When glucose and lactose are present e coli usually uses glucose When lactose is present and glucose is low e coli will use lactose Cyclic amp cAMP accumulates when glucose is scarce The regulatory protein called CAP an activator activates transcription by binding to DNA When camp binds to CAP cap assumes its active shape and can facilitate the binding of rna poly to the promoter and therefore directly stimulates transcription When acetyl groups are attached to lysines in histone tails in chromosomes When lysines are acetylated the positive charges are neutralized and therefore cannot bind when chromatin binding doesn t occur the chromatin has a looser structure Loose structure transcription proteins having an easier access to genes Formation of a diploid zygote from a haploid egg and sperm Sperm penetrate dissolves protective egg layer to reach plasma membrane Molecules on the sperm bind to receptors on egg surface to ensure that a sperm of same species fertilizes the egg Acromosomal reaction Fusion of sperm and egg triggering depolarization Na ions Increase in Ca2 concentration Cortical reaction Begins with discharge of hydrolytic enzymes from the acromosome These enzymes help digest the jelly coat Fast block to polyspermy Slow block to polyspermy Granules in egg fuse with plasma membrane and from fertilization envelope Entry of multiple sperm nuclei into the egg Ca2 high concentration After fertilization Blastula Blastoceol Yolk Holoblastic Meroblastic Vegetal pole Animal pole Morphogenesis gastrulation organogenesis gastrulation Ectoderm Endoderm Mesoderm End of cleavage in humans Trophoblast Gastrulation is sea urchins Blastopore Gastrulation in frogs Rapid cell division that creates smaller cells called blastomeres 5 7 divisions that creates a hollow ball of cells A fluid filled cavity that is surrounded by the blastula Usually in vegetal pole and store of nutrients Cleavage furrow goes through entirely through Incomplete cleavage of yolk rich egg birds Where egg yolk concentration is highest Lower concentration of egg yolk Cellular and tissue based process where animal body takes shape there are two stages Cells at near surface of blastula move to interior cell layers established primitive digestive tube formed Formation of organs Reorganization of hollow blastula into a 2 3 layered embryo These layers are the cell layers germ layers Outer layer Epidermis Nervous system Lines digestive tract Between ectoderm and endoderm skeletal muscular systems circulatory and reproductive Creates a blastocyst One side of the blastocyst has a cavity called the inner cell mass Outer part of blastocyst Initiates implantation but doesn t contribute to embryo Begins at vegetal pole of the blastula Invagination begins where sheet cells begin to fold over and buckle inward Extensive rearrangement of cells transforms the shallow depression into a deeper narrow tube called the archenteron Then after the open end of the archenteron becomes the blastopore a second opening dfor the mouth forms on the opposite end of the archenteron when the archenteron touches the inside of t he ectoderm and the two layers fuse creating the digestive tube The open end of the archenteron which will become the anus The blastula for frogs is a large yolk laden cell in the vegetal hemisphere Frogs are bilaterally symmetrical animals so they have a dorsal front side ventral side bottom left and right side and then anterior front and posterior back side Gastrulation begins when a small indented crease the blastopore appears on the dorsal side of the late blastula the crease is formed by the cells invaginating The outer cell sheets then roll inward on the dorsal lip which is the part above the crease and then move to the interior which then forms the endoderm and mesoderm At the animal pole cells change shape and begin to spread over the outer surface The blastopore
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