Chapter 1

Question 1

What is the blending theory of inheritance?

Answer 1

Commonly held view that inheritance worked like the mixing of fluids such as paints
Red and white paints give pink
One tall parent and one short parent yield middle height child

Question 2

What did Gregor Mendel do?

Answer 2

Australian monk who worked to understand rules that govern transmission of traits after hybridization among variety of pea plants
Cross pollinated or intermated different varieties of the pea plant
Discovered 2 particles each parents had that control traits (these were genes)
Determined one allele is dominant to other as well

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Question 3

What are alleles?

Answer 3

One of the variants a gene can come in

Ex: purple and white alleles for flowers in Mendels experiment (purple is dominant allele)

Question 4

How was Mendel’s work rediscovered?

Answer 4

He originally published in 1866 but it’s implications and importance went under appreciated for over 30 years
William Bateson became a relentless apostle of Mendel’s work and later coined the term genetics (study of inheritance)

Question 5

What is the chromosome theory of inheritance and who proved it?

Answer 5

Chromosome theory demonstrates that Mendel’s genes are located on chromosomes

First proposed by Walter Sutton
Proved by Thomas H Morgan using fruit flies

Question 6

What is the multifactorial hypothesis?

Who discovered it?

Answer 6

States that continuous traits are controlled by multiple Mendelian genes
Discovered by Ronald Fisher

Question 7

What is the one-gene-one-enzyme hypothesis?

Who discovered it?

Answer 7

States that genes encode enzymes that perform metabolic functions within cells

Edward Tatum and George Beadle used bread mold

In the case of pea plant, there is a gene that encodes an enzyme required to make the purple pigment in the cells of a flower

Question 8

Who were the first to give compelling evidence that genes are made of deoxyribonucleic acid (DNA)?

Answer 8

Oswald Avery
Colin MacLeod
Maclyn McCarty

Showed DNA extracted from a virulent strain of bacteria carried the necessary genetic information to transform a nonvirulent strain into a virulent one

Question 9

Who discovered the molecular structure of DNA and what is it?

Answer 9

James Watson and Francis Crick discovered the double helix model of DNA
2 strands of DNA wound side by side like a ladder
The rings of the latter were made up of 4 bases:
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
the bases face the center and each base is hydrogen bonded to the other base facing the other way
Adenine always paired with thymine by double hydrogen bond
Guanine always paired with cytosine by triple hydrogen bond

Question 10

How are genes regulated?

Answer 10

Genes have regulatory elements that regulate gene expression (whether a gene is turned on or off)
Regulatory elements are specific DNA sequences to which a regulatory protein bonds and acts as activator or repressors

Question 11

What is the central dogma of molecular biology?

Answer 11

Phrase introduced by Francis Crick to represent the flow of genetic information within cells from DNA to RNA to protein

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Question 12

What is DNA replication?
What is transcription?
What is translation?

Answer 12

DNA rep- a copy of the DNA is produced by each of the 2 daughter cells having a complete copy of all the DNA in the parent cell

Transcription- RNA synthesis from DNA template (mRNA made by transcription)

Translation- translating specific sequence of bases in the mRNA into the sequence of amino acids that compose a protein

Question 13

What is a codon?

Answer 13

Set of 3 consecutive nucleotides in the mRNA that specifies an amino acid in a protein

Question 14

What are model organisms?

What are the 4 things that make a good model organism?

Answer 14

Species used in experimental biology with the presumption that what is learned from the analysis of that species will hold true for other species, especially close related species

1. Small organisms that are easy and inexpensive to get
2. Short generation time to study more generations
3. Small genome is useful, easier to find genes looking through small genome
4. Easy to cross or mate and that produce large numbers of offspring are best

Question 15

What are DNA polymerases?
Nucleases?
Ligases?

Answer 15

DNA polymerases- make a copy of a single DNA strand by synthesizing a matching strand with the complete complementary sequence of As Cs Ts Gs

Nucleases- cut DNA molecules in specific locations or degrade an entire DNA molecule into single nucleotides

Ligases- can join 2 DNA molecules together end-to-end using DNA polymerase or other enzymes

Question 16

What is transformation in genetics?

Answer 16

Geneticists have developed methods to insert foreign DNA molecules into the genomes of many species

Can transform genes of one species into the genome of another
Recipient then becomes a genetically modified organism (GMO)

Question 17

How are geneticists using hybridization?

Answer 17

Hydrogen bonds of DNA strands can be broken by heat (denature) in aqueous solution to give 2 single stranded DNA molecules
Solution is cooled and DNA will preferentially hybridize with one another

Question 18

What is DNA sequencing?

Answer 18

Method used to determine the exact sequence of all the As, Cs, Gs, and Ts in the genomes, chromosomes, or genes of an organism

Question 19

What are single nucleotide polymorphisms (SNPs)?

Answer 19

Simplest form of genetic variation at a single nucleotide site
Difference in the nucleotide base present
Most common type of variation

Single nucleotide site in the genome where individual organisms in a population have different nucleotide bases

Top of page 16

Question 20

What are point mutations?

Which two scientists worked together on mutations first?

Answer 20

Change if one letter in the DNA code to another that can occur during DNA replication

Wilhelm Weinberg and JBS Haldane

Question 21

What is a de novo point mutation?

Answer 21

A unique variant that occurs in a child’s DNA that is not in either of its parents (top of page 18)
These ones arise in germline (special lineage of cells that divide to produce eggs in women and sperm in men)

Question 22

What is the difference of contributing new mutations to their offspring between fathers and mothers?

Answer 22

Fathers contribute 4 times as many new mutations to their offspring as do mothers

The number of new mutations passed on from a father to his children rises with the age of the father

Question 23

What us quantitative trait locus (QTL)?

Answer 23

Genetic locus that contributes incrementally or quantitatively to variation for a trait
QTL have alleles that usually engender only partial changes such as the difference between a pale purple and a medium purple

Rice QTL example page 21

Question 24

What are ethylene response factors (ERFs)?

Answer 24

Genes that encode regulatory proteins that bind to regulatory elements in other genes and and thereby regulate their expression

Question 25

What are the 3 factors that are powerful in shaping the types of gene variants that occur in different human populations?

Answer 25

1. Pathogens such as malaria or small pox
2. Local climate conditions including solar radiation, temperature, and altitude
3. Diet, such as relative amounts of meat, cereals, or dairy products eaten

Question 26

What is a gene?
What is an allele?
What is a chromosome?

Answer 26

Gene- a chromosomal region that codes for a functional transcript
A functional unit of heredity

Allele- one of the different forms of a gene that exists at a single locus

Chromosome- long DNA molecules visible during mitosis
Large genetic element that carries genes essential to cellular function

Question 27

What is mendels first and second laws?

Answer 27

First law- alleles of a single gene segregate independently from eachother

Second law- alleles of different genes segregate independently from eachother