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Flashcards in Genetics 2 Deck (28):
1

protein synthesis is

the process where information encoded in the genome is translated into specific cellular function in the cytoplasm

2

genetic code=

sequence of adjacent bases ultimately determines the sequence of amino acids in the encoded poly peptide

3

rRNA

ribosomal RNA supports structural unit of the ribosomes

4

tRNA

transfer RNA is the link between code contained in base sequence of each mRNA and the AA sequence of the protein encoded

5

non transcribed strand=

coding or sense strand

6

transcribed strand=

non-coding or antisense strand

7

additions to primary DNA modification

addition of a chemical "cap" structure to the 5' end
-addition of polyA tail to 3' end

8

cleavage of ____ end in modification

cleavage of 3' end at specific point downstream from the coding information

9

polyA

location specified by sequence AAUAAA found in 3' untranslated portion of RNA transcript
provides stability to mRNA

10

prior to translation, how is RNA processed and spliced

-introns are removed
-exons are spliced together
(mRNA is then transported out of the nucleus and into the cytoplasm)

11

in translation, what does tRNA do

it brings the correct amino acid sequence into position

12

what are ribosomes

are macromolecular complexes made up of rRNA and are the sites of protein synthesis

13

initiator codon

AUG- methionine- establishes the reading frame for all subsequent codons

14

3 stop codons

UAA, UAG, UGA

15

post translational processing of polypeptide chain

-fold, bind, form 3D structure, combine (2 or more polypeptide chains) to form protein complex

16

what are transcription factors?

are specific proteins that regulate transcription

17

promoter sequence does

interacts with transcription factors

18

2 promoters found in tissue specific genes

TATA box
CAT

19

TATA box

conserved region rich in adenines and thymines
-appears to be important for determining the position of the start of transcription

20

CAT

conserved region
-involved in normal gene expression

21

what is the role of promoters

-play a role in gene regulation
-can be site of mutation that can interfere with its normal expression and function

22

house keeping genes (CG) are expressed where and contain what?

-expressed in most or all tissues that lack the CAT and TATA promoter boxes
-contain high proportion of cytosines and guanines

23

what do CG (house keeping genes) rich sequence elements serve as

serve as binding sites for specific transcription factors

24

what are house keeping genes associated with

repression of gene transcription
(cancer, genomic imprinting, X chromosome inactivation)

25

what do enhancers do?

stimulate transcription
-establishing tissue specificity
-level of expression on many genes

26

what is RNA splicing

splicing reactions guided by specific sequences in the primary RNA transcript at both 5' and 3'
GT at 5'
AG at 3'

27

how common are alternative transcripts

2 to 3 alternative transcripts per gene in the human genome

28

what does alternative splicing lead to

the synthesis of multiple related but different mRNAs, each of which can be subsequently translated to generate different protein products