1 Human Genome Flashcards

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1
Q

what is a locus?

A

physical position of a gene in a chromosome

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2
Q

what is dossage?

A

number of copies of a given gene in the genome

like in down sd more than 2 copies

or turner just one copy

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3
Q

what is allele

A

alternative form or alternative copy of a gene in a given locus

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4
Q

where do we get each allele from?”

A

one from mom and one from dad

  • homozygous (2 copies of same allele)
  • heterozygous (2 differetn copies
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5
Q

how many base pair on a:

  • kb
  • Mb
  • cM
A
  • kb 1000 bp
  • Mb 1 million bp
  • cM (centermorgan) ~1% recombination = 1MB
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6
Q

what is the genetic size in cM?

for females

for males

and the average

why females more than males?

A
  • females 4400 cM
  • males 2700 cM
  • sex-averaged 3700 cM

females more due to increased recombination

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7
Q

how many base pairs do we have in the human genome?

A
  • 6 x 109 diploid
  • 3 x 109 haploid
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8
Q

what is splicing?

A

its the editing of RNA

removing introns

and putting the exons together

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9
Q

is it correct to say ONE gene encodes for ONE PROTEIN?

A

NO… that is a very old concept.

ONE GENE can make multiple different proteins or products

For this reason, we used to say that there were 100K protein-coding genes but now we say there are 20K protein-coding genes

This is explained due to ALTERNATIVE SPLICING

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10
Q

what is the average size of protein-coding genes?

A
  • 14Kb
  • (range 2-2400 kb)
  • there are ~10 exons/gene
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11
Q

what is the average # of exons per gene?

A

~10 exons/gene

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12
Q

what % of genes produce more than one mRNA (and thus, more than once protein)

A

60%

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13
Q

which one of the biggest genes?

A

the dystrophin gene

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14
Q

DNA strands are parallel or anti-parallel?

A

anti-parallel

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15
Q

what sugars are in DNA and RNA?

A

DNA dexosiribose

RNA ribose

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16
Q

which are the TWO purines and the

THREE pirimidines?

A
  • Purines: A-G
    • A adenine
    • G guasnine
  • Pyrimidines TUC
    • C cytosine
    • T Thymine
    • U uracil
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17
Q

what are the pairs for ATCGU? foe each

A
  • A with T
  • C with G
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18
Q

what is DNA replication and how fast it happens?

A

its the DNA reproduction from 1 DNA to TWO daughters DNA

  • speed of 40 nucleotides/sec i eukaryotes
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19
Q

what is the DNA replicatio direction?

A
  • 5’ to 3’ leading strand
  • the other strand LAGGING STRAND is 3’ to 5’ is synthesized in pieces (okasaki fragments)
20
Q

what is translation and what is transcription?

A
  • DNA to RNA is TRANSCRIPTION
  • RNA into protein is TRANSLATION
  • remember the sequence is DNA to RNA to protein
  • remember your FIRST TRANSCRIBE
  • translators for next, translators need the paper written instructions.
21
Q

is it OK to say that genes code for proteins?

A

that is an old concept…

Genes code for FUNCTIONAL PRODUCTS

22
Q

what is ncRNA gene and how many

A

non-coding RNA genes

and there are the same number of coding genes so around 20K

the difference is that ncRNA genes are very small

23
Q

what is the gene structure?

A
  • Promoter (5’ info to start)
  • UTR untranscripted region
  • Exons
  • introns
  • termination codon
  • 3’ region
24
Q

what is the RNA difference in structure to DNA?

A

RNA has:

  • ribose
  • single stranded
  • Uracil replaces thymine
25
Q

synthesis of primary RNA occurs in which direction?

A

5’ to 3’

26
Q

which are achrocentric chromosomes?

A

13, 14, 15, 21, 22

27
Q

what is a robertsonian translocation

A
  • rare form of chromosomal rearrangement
  • occurs only in the 5 achrocacrocentricosomes
  • these are 13, 14, 15, 21, 22
  • its when 2 of these join together (by the q arms - no p arms)
  • most babies with robertsonian translocation (RT) have parents with normal chromosomes
  • some babies have one parent with a RT (carrier)
  • two types
    • balanced rob = healthy, carrier
    • unbalanced = chromosomal disorder
      • ex: Down’s syndrome
      • trisomy 13
      • Prader willi
      • Angelman
28
Q

what is Transcription and translation order?

A

transcription 5’ to 3’

Translation 3’ to 5’

29
Q

During transcription, which strand is transcribed?

A

The lower strand

30
Q

Synthesis of RNA in transcription occurs in which direction?

A

5’ to 3’

31
Q

Name some polymerases and what is their function?

A
  • Pol I
    • Transcribe rRNAs
  • Pol II
    • mRNA
    • microRNAs
  • Pol III
    • tRNA
  • Pol G
    • Mitochondrial
32
Q

To help in the splicing process there are 2 types on enhancers

A
  • ESE exon splicing enhancers
  • ISE intron splicing enhancers
  • They bind serine rich proteins and other factors to select splice sites
  • They tell where is the splicing
33
Q

What is translation? Where does it occur

A
  • RNA to protein synthesis
  • Goes 3’ to 5’
  • Occurs in ribosomes
34
Q

What is a codon?

A

Set of 3 bases that specify an AA

35
Q

What is the codon that initiates TRANSLATION?

A

ATG - Methionine (almost always) if embedded in Kozak

36
Q

How many AA have one codon? Meaning that only one codon combination forms them

A

TWO

  • Methionine AUG or AGG
  • Tryptophan UGG
37
Q

Which are the termination codons?

A

UAA, UAG, UGA

38
Q

Why do we say genetic code is degenerate?

A

Because most AA are specified by more than one codon

Changing the 1st base sometime changes the AA

Changing the 2nd base ALWAYS changes the AA

Changing the 3rd sometimes

39
Q

Which are the stop codons?

A
  • UGA
  • UAG
  • UAA
40
Q

What are the steps in translation?

A
  • Initiation
    • Methionine until AUG
  • Elongation
    • tRNA binds to A-site
  • Termination
41
Q

How many million bases in one CentiMorgan?

A

1 million bp on one Centimorgan

42
Q

Alternative transcription

A
  • In dystrophin protein for example
  • Similar to alternative splicing
43
Q

What is mRNA?

A

Messenger RNA

44
Q

Characteristics of tRNA?

A
  • Cloverleaf pattern
  • Together by hydrogen bonds
45
Q

What are the ribosome sites?

A

P & A sites

46
Q
A