1 - MOLECULAR BASIS OF GENETICS

Question 1

• Study of inherited traits, rooted in DNA, and their variations and transmission
• Started from plant breeding experiments
• Has evolved to become a major medical discipline

Answer 1

Genetics

Question 2

Transmission of traits and biological information between generations

Answer 2

Heredity

Question 3

• Functions as the units of heredity in that copies of genes are passed from one generation to the next
• Consists of the long molecule DNA

Answer 3

Genes

Question 4

People performed selective breeding of good traits and characteristics of animals they herded and domesticated. What animals are these?

Answer 4

Horses

Question 5

Important Events in Genetic History

• People performed selective breeding of good traits and characteristics of animals they herded and domesticated
• Later on was used in improving the quality of crops as well

Answer 5

8000-1000 BC

Question 6

8000-1000 BC

Father of Medicine proposed that invisible seeds found in the male semen serve as the bearers of the hereditary traits

Answer 6

Hippocrates

Question 7

8000-1000 BC

• Argued that the blood contained materials for building all parts of the body
• He believed that the semen was purified blood
• Further argued that some seeds from the blood would not appear until later in life

Answer 7

Aristotle

Question 8

18th Century

believed that miniature humans were found in the head of sperm cells called homunculus

Answer 8

Concept of Preformation

Question 9

18th Century

confirmed that all organisms were derived from cell

Answer 9

Cell Theory

Question 10

18th Century

• Proposed the theory of natural selection
• Stated that the best adapted characteristics of parents are those that get carried over to their children
• Overtime, these new characteristics combined leading to the birth of a new species

Answer 10

Charles Darwin

Question 11

1865

experimented with pea plants and established basic rules of heredity and made him “Father of Modern Genetics”

Answer 11

Gregor Mendel

Question 12

1944

confirmed that it was DNA that carried the genetic information

Answer 12

Avery

Question 13

1953

discovered the double helix structure of DNA

Answer 13

Watson and Crick

Question 14

1956

Diploid number of chromosomes was identified as?

Answer 14

46 chromosomes

Question 15

1956

Haploid number of chromosomes was identified as?

Answer 15

23 chromosomes

Question 16

1959

• Showed that Down Syndrome is a chromosomal abnormality
• First identification of the genetic basis of a disease

Answer 16

J. Lejenne

Question 17

1975

This allowed the detection of specific DNA sequences

Answer 17

Southern blot

Question 18

1977

developed the chain termination method for sequencing DNA

Answer 18

Fred Sanger

Question 19

1983

Localization of Huntington’s disease

Answer 19

chromosome 4

Question 20

1985

developed the PCR which provided a rapid way to make many copies of DNA molecules

Answer 20

Mullis & co-workers

Question 21

1989

identified as the gene causative for cystic fibrosis when mutated

Answer 21

Cystic fibrosis transmembrane conductance regulator gene on chromosome 7

Question 22

1990

• $3 billion, 15-year project with the goal to sequence the human genome
• The endgame of the project was to determine the genres associated to diseases and predict and possible diseases in the future

Answer 22

Human Genome Project

Question 23

Formed by linking multiple nucleotides

Answer 23

DNA

Question 24

Basic unit of the DNA

Answer 24

Nucleotides

Question 25

Components of nucleotides

Answer 25

Nitrogenous base Sugar Phosphate

Question 26

6-membered ring containing 2 nitrogens

Answer 26

Pyrimidines

Question 27

9-membered ring consisting of 2 rings

Answer 27

Purines

Question 28

Types of Pyrimidines

Answer 28

Cytosine Uracil Thymine

Question 29

Types of Purines

Answer 29

Adenine Guanine

Question 30

5 membered rings of sugar

Answer 30

Pentoses

Question 31

2 types of sugars

Answer 31

Ribose Deoxyribose

Question 32

Components of nucleoside

Answer 32

Sugar Nitrogenous base

Question 33

* Forms the backbone of the DNA * One chain runs in 5’ to 3’ direction while the other is 3’ to 5’

Answer 33

Phosphate

Question 34

* Bond that holds the different nucleotides together * Links the 3’ carbon of one sugar to the 5’ carbon of the next sugar

Answer 34

Phosphodiester bonds

Question 35

Formation of protein from DNA

Answer 35

Central Dogma

Question 36

* First step in gene replication * Because the DNA is too big to exit the nucleus, a small copy of it must be created and exits to the cytoplasm * A DNA strand molecule splits by the help of RNA polymerase enzyme * Nucleotides complementary to the template strand are formed on the RNA

Answer 36

Transcription

Question 37

* The mRNA is translated to synthesize proteins * Each amino acid is formed by 3 nitrogenous bases * In the cell cytoplasm, the ribosome reads the sequence of the RNA in groups of three bases * An anticodon or complementary codon is matched to the RNA coding for a specific amino acid

Answer 37

Translation

Question 38

start codon

Answer 38

AUG (methionine)

Question 39

stop codons

Answer 39

UAA, UGA, UAG

Question 40

The process of forming more copies of DNA

Answer 40

Replication

Question 41

separates DNA strands

Answer 41

Helicase