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Biology 1 > Molecular Genetics > Flashcards

Molecular Genetics Flashcards

1
Q

What are the complementary base pairs in nitrogenous bases

A

AT double bond

CG triple bond

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2
Q

Nucleoside vs nucleotide

A 
Side = base + ribose sugar
Tide = base + sugar + phosphate ( t = t)
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3
Q

Explain the semi conservative process of DNA replication

A

Helicase unzips Parent DNA
RNA polymerase creates an RNA primer.
DNA polymerase 3 adds complementary nucleotides on the 3’ end (5’-3’)
RNAse H removes primers
Gaps are filled by DNA polymerase 1 and any nicks are sealed by ligase

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4
Q

Explain the difference between leading and lagging strand and why that’s a thing

A

Nucleotides can only be added from 5’ - 3’
Leading is continuously synthesized only requiring one primer
Lagging stars and has Okazaki fragments that require many primers

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5
Q

Difference between prokaryote and eukaryote DNA replication

A

Pro - 1 origin of replication on each circular chromosome (plasmid)
Euk - multiple origins on each linear chromsome

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6
Q

All nucleotide processed go in which direction

A

5’ to 3’

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7
Q

What does telomerase do

A

Lengthen the end of eukaryotic chromosome with telomeres

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8
Q

Define gene vs genome

A

Series of DNA nucleotides that code for an RNA product

Genome contains the entire DNA sequence of an organism

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9
Q

what is the central dogma *****

A

DNA is transcribed into RNA which is translated into amino acids (proteins)

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10
Q

4 differences of RNA to DNA

A

can leave the nucleus (DNA only in nucleus and mitochondria
Uracil instead of thymine
Has an OH group
Single stranded

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11
Q

Primary rna

A

Immature strand of mRNA

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12
Q

Messenger rna

A

Primary rna is processed to encode for a blueprint used in translation

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13
Q

Ribosomal rna

A

Rna component of a ribosome

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14
Q

Transfer rna

A

Transfer amino acids to growing polypeptide

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15
Q

3 phases of transcription

A

Initiation , elongation, termination

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16
Q

Initiation phase of transcription

A

RNA polymerase binds to promoter or TATA box then unzips DNA and forms a transcription bubble

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17
Q

Elongation phase of transcription

A

RNA polymerase transcribes the template (antisense) strand adding nucleotides 5’-3’ creating a primary RNA transcript with the same sequence as the coding strand (sense)

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18
Q

mRNA strand made in transcription is complementary to _____ and the same as ______

A

Complements the template strand
Same as the coding strand
** uracil instead of thymine

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19
Q

Termination phase terminates transcription which it hits which sequence

A

UAA UAG UGG

Remember on the template strand UAA would be ATT and coding strand would be TAA

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20
Q

Do page 59 in classroom companion**

A

Ok

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21
Q

3 types of post transcriptional modification

Does this occur in bacteria mRNA?!

A

MRNA in bacteria are translated directly into a protein. eukaryotes undergo

  1. 5’ cap methyl guanine cap is added to 5’ end protects from degradation by exonucleases
  2. Poly A tail on 3’ end , the string of adenin protects from degradation
  3. Splicing - introns are cleaved and Exxon’s are spliced together by snRNPs
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22
Q

What is a ribozymes

A

RNA molecule that can catalyze reactions , one of the few enzymes that’s not a protein

23
Q

What happens to mRNA after post transcriptional modification

A

Exons Exit the nucleus into cytoplasm to undergo translation

24
Q

Start codon

A

AUG

25
Q

MRNA nucleotides strung together form the genetic code which has 3 key features

A

Unambiguous - codes from a specific amino acid
Degenerative - an amino acid can have more than one code
Universal - all living organisms use the same code except the mitochondria

26
Q

What are the sedimentation coefficients of prokaryotic and eukaryotic ribosome

A

Pro - 30 + 50 (70)

Euk - 40 + 60 (80)

27
Q

Describe translation process

A

TRNA with methionine enters P site to form initiation site. C end binds to N end of amino acid in a dehydration reaction. That tRNA goes to E site and exits while a new tRNA comes to A site until a stop codon reaches the A site

28
Q

Ditrection of translation

A

5’ to 3’ and N to C

29
Q

Is there proof reading in translation , transcription , replication

A

No
Reduced
High and fast

30
Q

Key differences between prokaryotes and eukaryotes in transcription/translation

A

Pro - not membrane bound so can occur simultaneously therefore less regulation and control
Euk - transcription in nucleus, translation in cytosol

31
Q

When you come across a membrane bound protein (functions in ER rather than cytosol) how was it created

A

First couple of amino acids form a signal peptide that is recognized by RNA signal recognition particle that binds and then carries the ribosome complex to SRP receptor protein on the endoplasmic reticulum
The N terminus of the peptide is orientated into the lumen (interior) and translation resumes with the peptide growing inside the lumen!

32
Q

Difference between posttrascriptional control and posttranslational

A

Transcript - 5’cap, poly A tail, splicing

Translat - how proteins are folded, carbs or lipids added, exported

33
Q

Silent point mutation

A

Codon codes for same amino acid

34
Q

Missense point mutation

A

Codon codes for different amino acid that may or may not impact the protein

35
Q

Nonsense

A

Changes to stop codon resulting in non functional protein

36
Q

Frameshift

A

Insertion not in a multiple of 3 alters the reading frame

37
Q

Nonframeshift mutation

A

Multiple of 3 nucleotide inserted into gene sequence

38
Q

Explain what goes wrong that cancer cells form

A

No apoptosis
Proto-oncogene is a normal gene that becomes an oncogene due to a mutation often caused by a carcinogen
Loss of tumor suppressor gene

39
Q

How does DNA become a chromosome

A

DNA wraps around his tones to form nucleosides which become a solenoid then chromatin which become chromosomes

40
Q

What is a chromosome

A

Organized DNA+protein structure in the nucleus

Single double helix of coiled DNA that contains genes

41
Q

Cell cycle for somatic cells consists of mitosis and interphase , what are the stages of interphase

A

after mitosis G0 = cell arrest
G1 = growth
S = 46 chromosomes duplicated into sister chromatids
G2 = double check

42
Q

What is mitosis and what does it produce

A

Nuclear cell division * no genetic change

2 genetically identical daughter cells with 46 chromosomes

43
Q

4 phases of mitosis

A

Prophase - chromosome condenses, spindle forms
Metaphase - chromosomes align
Anaphase - sister chromatids separate, cytokinesis begins
Telophase - new nuclear membrane forms

44
Q

What does diploid mean

A

Cell has homologous pairs

45
Q

In the nucleus of a human cell there are 46 chromosomes before replication, how many are there after replication

A

46 chromosomes still!!!!

Refer to duplicates as sister chromatids, this is a very important concept

46
Q

What is the result of meiosis

A

Four haploid gametes from a single diploid germ cell

47
Q

What happens during prophase 1 of meiosis

A

Homologous chromosome s(same genes) form a tetrad which is held together at the chiasmata where crossing over of genetic material occurs

48
Q

Product after meiosis 1

A

Haploid 23 chromosomes / 46 chromatids

49
Q

3 ways eukaryotes increase genetic diversity

A

Crossing over in prophase 1
Random assortment in metaphase 1
Fertilization

50
Q

What is nondisjunction and how serious is it

A

Failure of chromosome pairs to separate at anaphase resulting in aneuploid cells which is not much of an impact on somatic cells but can be severe in embryogenesis

51
Q

Monopoly vs trisomy

A

Mono - loss of single chromosome in zygote - often not viable
Tri - addition of chromosome in zygote

52
Q

See page 90 for differences between mitosis and meiosis

A

Ok

53
Q

how are dna nucleotides linked

A

covalent phosphodiester bond formed by dehydration between OH of 3’ carbon and the phosphate attached to the 5’ carbon

Biology 1 (5 decks)

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