Lec 13,14 DNA & Genetics

Question 1

What is nucleotide base structure

Answer 1

nitrogenous base+sugar+phosphate

Question 2

Bases-Nitrogen containing ring compounds
What are the two major types

Answer 2

purine and pyrimidine

Question 3

how many rings does purine have and what are the nucleotides

Answer 3

two rings: adenine (A) and guanine (G)

Question 4

how many rings does pyrimidine have and what are the nucleotides

Answer 4

one ring: cytosine (c) and thymine (t) and uracil (u)

Question 5

Nucleotide sugars- _C sugar
what are the two major types

Answer 5

5C sugar
two major types: ribose and deoxyribose

Question 6

what are the kinds of phosphates a nucleotide can have

Answer 6

mono-
di-
or triphosphate

Question 7

what does DNA stand for

Answer 7

deoxyribonucleic acid

Question 8

DNA structure
what are the 4 building blocks

Answer 8

A
T
G
C

Question 9

DNA complementary base pairing:
what does A pair with?
what does G pair with?

Answer 9

A pairs with T
G pairs with C

Question 10

how many hydrogen bonds does A and T form

Answer 10

2 hydrogen bonds

Question 11

how many hydrogen bonds does G and C form

Answer 11

3 hydrogen bonds

Question 12

DNA double strand
what is anti-parallel held by

Answer 12

hydrogen bonds

Question 13

DNA double helical structure
what is diameter
what is number of base pairs/helical turn
what is nm/helical turn

Answer 13

diameter: 2 nm
10 base pairs/helical turn
3.4 nm/helical turn

Question 14

what was Mendel experiment and results

Answer 14

yellow pea x green peas -> all yellow peas (F1)-> yellow is dominant over green
F1 yellow peas x F1 yellow peas-> yellow peas and green peas (3:1 ratio)

Question 15

Mendel law of segregation

Answer 15

the two alleles for each trait separate during gamete formation

Question 16

what does mendel law of segregation apply to

Answer 16

applies to all sexually reproducing organisms

Question 17

Mendel law of independent assortment

Answer 17

alleles for different traits segregate and assort independently
form the results of dihybrid cross
only true for the genes that are on different chromosomes or are separated at a distance on the same chromosome

Question 18

exceptions to Mendel’s law
what is polygenic inheritance

Answer 18

traits that are determined by multiple genes
traits that show continuous variation
each gene makes a small contribution to the phenotype

Question 19

exception to mendel law
incomplete dominance

Answer 19

the dominant allele is not fully dominant
a cross between two heterozygous parents results in 1:2:1 ratio (instead
of 3:1)

Question 20

Exception to mendels law
what is codominance

Answer 20

each allele of the gene expressed and determines the phenotypes
human blood type is determined by the sugar molecules on the surface of red blood cells

Question 21

example of multiple alleles
exceptions to mendels law

Answer 21

Human ABO blood type

Question 22

exceptions to mendels law
what are environmental influences

Answer 22

temperature-sensitive allele of genes

Question 23

each DNA strand has a backbone that consists of what

Answer 23

sugar and phosphates

Question 24

the end of each chromosome contains what?

Answer 24

telomeric repeats

Question 25

what is the ratio for a dihybrid cross for phenotypic ratio

Answer 25

9:3:3:1

Question 26

for a trait to meet Mendel law the trait has to have how many genes and how many alleles

Answer 26

one gene with two alleles

Question 27

What is and what does telomerase do

Answer 27

complex formed by reverse transcriptase and telomere RNA
it synthesis DNA using an RNA template
Its function is to maintain DNA length

Question 28

what does low level of UV radiation cause

Answer 28

thymine dimer

Question 29

what is result of deamination of a cytosine base

Answer 29

point mutation

Question 30

what do nucleotides consist of

Answer 30

nitrogen containing base
a 5-carbon sugar
one or more phosphate group

Question 31

what is karyotype and what is humans

Answer 31

each chromosome is a linear DNA molecule
human has 22 pairs

Question 32

mendel garden pea experiment what are the three stages

Answer 32

1) produce true breeding strains for each trait
2) cross-fertilize true breeding strains
3) allow for hybrid offspring to self-fertilize for several generations and count the number of offspring showing each form of the trait

Question 33

explain what a gene is

Answer 33

inheritance of traits is governed by hereditary factors

Question 34

explain what a allele is

Answer 34

different versions of gene account for the variation

Question 35

what is monohybrid cross and what is result

Answer 35

cross between parents that are heter for a single trait
1:2:1 ratio
25% YY 50% Yy 25% yy

Question 36

what is dihybrid cross and what is result

Answer 36

cross between parents that are heterozygous for two traits
9:3:3:1