The Hereditary Material - MT3 - Part 1

Question 1

What is the only molecule recognizable from its shape?

Answer 1

DNA

- double helix

Question 2

What lead to the discovery of the structure of DNA?

Answer 2

History of the study of the hereditary material

Question 3

What 2 streams consisted from the DNA?

Answer 3

1. Genetic function

2. Structure of macromolecules

Question 4

What was the DNA structure very suggestive for?

Answer 4

Function

Question 5

What was the function they proposed from the structure of DNA?

Answer 5

Replication

Question 6

Who discovered DNA?

Answer 6

Friedrich Miescher

Question 7

How did Miescher discover DNA?

Answer 7

He isolated nuclei from pus and found a new kinda of molecule called nuclein

Question 8

Who discovered the shape of DNA?

Answer 8

Watson

Question 9

What does pus have a lot of?

Answer 9

RBC

Question 10

What does DNA have? (2)

Answer 10

1. Both acidic and basic parts
   - but mostly acidic
2. Lots of phosphorus

Question 11

What did Miescher suspect was involved in heredity? And why?

Answer 11

Thought that nuclein might be involved in heredity because the significance of nuclei in hereditary had been established

Question 12

What did Miescher think might be hereditary variants?

Answer 12

Isomers of nuclein

Question 13

What did Albrencht Kossel find out?

Answer 13

That there are 5 kinds of bases

Question 14

What are the 5 kinds of bases?

Answer 14

1. Adenine
2. Guanine
3. Cytosine
4. Thymine
5. Uracil

Question 15

What did Phoebus Aaron Leven do? (3)

Answer 15

1. Elucidated the structure of nucleotides
2. Determined the difference between DNA and RNA and their sugars
3. Proposed the tetranucleotide model of DNA

Question 16

What did Leven’s analysis suggest?

Answer 16

That the 4 bases of DNA were present in equimolar amounts

- in equal numbers

Question 17

What was discovered about Leven’s model?

Answer 17

That it was wrong

• thought it was proteins instead of DNA
• proteins are not hereditary

Question 18

What did Archibald Garrod study?

Answer 18

Alcaptonuria

- soon after the rediscovery of Mendels law

Question 19

What did studying family pedigrees show?

Answer 19

That alcaptonuria is inherited as a Mendelian recessive trait

Question 20

Alcaptonuria

Answer 20

Is a rare inherited genetic disorder in which the body cannot process the amino acids phenylalanine and tyrosine, which occur in protein

Question 21

What are alcaptonuria not able to get ride of?

Answer 21

Homogentisic acid

Question 22

What happens when homogentistic acid builds up? (2)

Answer 22

1. It is excreted in the urine

2. Turns black upon exposure to air

Question 23

What did Garrod suspect about alcaptonuria?

Answer 23

A deficiency in a pathway which lacked enzymatic function since it could not encode for that enzyme

Question 24

What did Garrod conclude?

Answer 24

That a normal allele somehow produced an enzyme for the metabolism of homogentisic acid
- the alcaptonuric allele produced a defective or missing enzyme

Question 25

What did Franz Moewus study?

Answer 25

The genetics of sexuality in chlamydomonas eugametos | - which is a green unicellular alga

Question 26

What did Moewus associated with Mendelian mutations?

Answer 26

With an inability to produce sex hormones, thus associating genes with biochemical functions - same as Garrod had done

Question 27

What was Moewus accused of?

Answer 27

Making up data

Question 28

What were mutations in Neurospora Crassa (a fungus) associated with?

Answer 28

Deficiencies in pathways that synthesize amino acids from precursor molecules

Question 29

Mutagenesis

Answer 29

Ia a process by which the genetic information of an organism is changed, resulting in mutation

Question 30

How might mutagenesis occur in nature? (2)

Answer 30

1. Spontaneously 2. As a result of exposure to mutagens - can also be achieved in the lab

Question 31

Genetic dissections

Answer 31

A major tool of developmental geneticists is the ordering of gene in functional pathways

Question 32

What did George Beadle and Edward Tatum perform?

Answer 32

The famous experiment of mutants having deficiencies in certain precursor pathways to synthesize amino acids for later precursor molecules - one gene = one enzyme (idea)

Question 33

What was the first protein to be studied in structural and functional detail?

Answer 33

Hemoglobin (Hb) | - modle molecule

Question 34

Why is Hb a model molecule? (3)

Answer 34

1. Can get a lot of it in pure substance 2. Easily accessible 3. Ability to quickly purify

Question 35

What could Pauling and co-workers show?

Answer 35

That a disease known to be inherited in simple Mendelian fashion, sickle cell anemia, was associated with a malformed version of a protein, Hb

Question 36

What do mutated proteins have? (3)

Answer 36

1. Different structures 2. Different functions 3. Can move at different migration speeds