Bio 351 Exam 1 (120 Questions) With
Correct Answers New Update
Development - answer ✔ - progressive and continuous change that generates a complex
multicellular organism from a single cell
Ex: 24 hour embryo dev. Of zebra fish
Transcription factors - answer ✔ - proteins that help turn specific genes "on" or "off" by
binding to nearby dna
-activators/repressors
Enhancer/silencer - answer ✔ - groups of transcription factor binding sites
-can turn a gene on/off in specific parts of the body
Promoter - answer ✔ - rna polymerase/transcription factors attaches to this spot on the dna
-in euk, needs basal (general) transcription factors
(tata box +mrna)
Tata box - answer ✔ - crucial promoter dna sequence that transcription factors recognize
Polya signal - answer ✔ - signal to end transcription and add a polya sequence at the end of
the transcript
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Splice acceptor - answer ✔ - signal at the 3- end of the intron
Aug - answer ✔ - starts translation
Enhancers- specific - answer ✔ - activates transcription-gata
-still affects gene even if far away,
-has flexibility in orientation and location
-responds to surrounding transcriptional factors
-can work upstream or downstream (5-3,3-5)
-tissue specific, modular (can bind to many different transcription factors (coding for
different gene expression) but not at the same time)
Intron - answer ✔ - a noncoding, intervening sequence within a eukaryotic gene
-gets spliced out of the pre-mrna
-removed through formation of a spliceosome loop structure, then exons are joined together
Differential rna processing - answer ✔ - the splicing of mrna precursors into messages that
specify different proteins by using different combinations of potential exons
Alternative rna splicing - answer ✔ - producing wide variety of proteins from the same gene
(-through enhancers making multiple cells with multiple functions (instead of multiple with
1 function)
Myostatin - answer ✔ - key inhibitor to muscle growth
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Embryonic cells differentiate into specialized adult cell types like - answer ✔ - endoderm,
mesoderm, ectoderm, germ cells
Steps of cell differntiation - answer ✔ - 1) commitment
2) differentiation
Commitment - answer ✔ - the cell's developmental fate has been restricted
-expressed through gene expression, not by change in function or morphological features
-change the genes that are expressed, turn some off vs on
Differentiation - answer ✔ - the generation of specialized cell types from committed
precursors
-full phenotype/function changed
-differentiate from muscle or neuron cell
Commitment steps - answer ✔ - 1) specification
2)determination
Specification - answer ✔ - after a given set of signals, cells differentiate in a neutral
environment
1) autonomous specification- cell tells fate from parental cells without interacting with other
cells (invertebrates)
2) conditional specification- achieve their fate through cell to cell communication
(juxtacrine, paracrine, or physical properties (mechanical stress)) (vertebrates)
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