genetics

Question 1

gregor mendel

Answer 1

In school bright but not successful
Financial difficulties lead to joining the monastery in Moravia (Czech) (1840s)
1860s published his genetic theories
Not thought important until rediscovered in the early 1900s

Question 2

mendel’s contributions

Answer 2

Discrete physical unit responsible for each trait
Passed from parent to offspring and through generations
Passage determined by mathematical laws
Trait doesn’t disappear if it’s not shown

Question 3

mendel’s reasons for success

Answer 3

Followed progress of hybrids through a number of generations
Selected plants that possessed contrasting characteristics
Used a large number of plants

Question 4

mendel’s experiments

Answer 4

Hypothesized that green trait not lost or altered

Yellow trait simply dominant and green trait recessive

Question 5

principle of segrigation

Answer 5

Genes occur in pairs. During the production of gametes, the pair is separated and each gamete contains only one of the pair

Question 6

principle of independent assortment

Answer 6

Distribution of one pair of genes does not influence the distribution of other pairs of genes

Question 7

gene

Answer 7

Entire sequence that codes for a protein

Question 8

mitosis

Answer 8

Normal cell division
Results in 2 daughter cells identical to the mother cell
Growth of organism
Replace old cells
Occurs only in somatic cells

Question 9

meiosis

Answer 9

Reduction division
Preparation of DNA for transmission to the offspring
Results in the formation of gametes

Question 10

meiosis functions

Answer 10

Diploid becomes haploid
Combination of mother’s and father’s genetic material
Recombination and crossing over
Transmission of mother’s mtDNA

Question 11

replication of dna

Answer 11

Two strands unwind
Strands separate
2 single strands attract free DNA nucleotides
Result is 2 identical double strands of DNA

Question 12

Transcription

Answer 12

Two strands of DNA unzip
One strand of DNA attracts RNA
RNA copies the DNA in complimentary form (mRNA)

Question 13

Translation

Answer 13

mRNA migrates out of the nucleus
mRNA is attracted to a string of ribosomes (rRNA)
Ribosome moves along the mRNA strand “reading” the genetic message
tRNA is attracted via the ribosome who brings with it the anticodon
Chain of amino acids is formed

Question 14

proteins

Answer 14

Structural components
Enzymes (chemical reactions)
Hormones
Direct and perform all physiological and cellular functions
“Genes” code for proteins

Question 15

codominence

Answer 15

both traits are present and distinguishable

Question 16

incomplete dominance

Answer 16

traits blend together

Question 17

polygenetic inheritence

Answer 17

Many genes code for the same thing
Continuous traits
Influenced by alleles at two or more loci, each make a contribution to the phenotype

Question 18

Genetic and environmental factors

Answer 18

Many polygenic traits influenced by environmental conditions

Question 19

pleiotropy

Answer 19

One trait codes for many things

Several seemingly unrelated phenotypic effects are influenced by the action of a single gene

Question 20

Evolution is a two stage process

Answer 20

Production and redistribution of variation

Natural selection acting on the variation differentially affect successful reproduction

Question 21

modern synthesis

Answer 21

Until 1930’s either mutation or natural selection was viewed as the prime mover of evolutionary change

Question 22

mutation

Answer 22

Molecular alteration in genetic material
To be evolutionary significant must occur in sex cells
Only way to produce new genetic variation

Question 23

gene flow

Answer 23

Exchange of genes between populations

Question 24

genetic drift

Answer 24

Random factor in evolution directly tied to population size
Some individuals can contribute a disproportionate share to genes to succeeding generations
Founder effect

Question 25

founder effect

Answer 25

A few members of on population start a new population with different allele frequencies than the original

Question 26

recombination

Answer 26

Both parents contribute genes to offspring so genetic information is reshuffled
Does not change allele frequencies but does produce new genetic combinations for natural selection to act on

Question 27

four causes of evolution

Answer 27

natural selection
mutation
gene flow
genetic drift