mendelian inheritance 1, probability and patterns- lecture 8

Question 1

aneuploidy

Answer 1

gain or loss of chromosomes which can result from nondisjunction

Question 2

trisomy 21 is caused by

Answer 2

non-disjunction in either
Meiosis I or Meiosis II

Question 3

Meiosis I non-disjunction

Answer 3

both homologous chromosomes are involved in the potential trisomy

Question 4

Meiosis II nondisjunction

Answer 4

both chromosomes involved will be from just one of the homologous chromosomes (former sister chromatids)

Question 5

dosage imbalance

Answer 5

leads to uneven numbers of gene
products, disrupting homeostasis as discussed previously with Trisomy 21

Question 6

heterokaryotype

Answer 6

heterozygous with one normal
chromosome and one rearranged chromosome

Question 7

if the number of genes on a chromosome is a predictor of the impact of extra copies of the chromosomes, why are 13 and 18 listed s the most frequent instances of non lethal trisomy rather than chromosomes 20 and 22 which are smaller

Answer 7

Question 8

what gives the indication of the parent of origin

Answer 8

Question 9

haploid

Answer 9

Haploid refers to the presence of a single set of chromosomes in an organism’s cells. Sexually reproducing organisms are diploid (having two sets of chromosomes, one from each parent). In humans, only the egg and sperm cells are haploid.

Question 10

diploid

Answer 10

(of a cell or nucleus) containing two complete sets of chromosomes, one from each parent.

Question 11

polyploidy

Answer 11

having whole extra sets of chromosomes

ex: selecting genes to make strawberry be bigger

Question 12

autopolyploidy

Answer 12

Question 13

examples of heterokaryotype

Answer 13

Question 14

meiotic problems

Answer 14

unequal crossing over
chromosomal inversion/deletion/addition in heterokayotype

Question 15

unequal crossing over

Answer 15

mispairing between closely related genes (like opsins) removes and adds to gene family

Question 16

opsin genes

Answer 16

Question 17

how do opsin genes lead to color blindness

Answer 17

Question 18

problem with gene duplication

Answer 18

dosage imbalance

Question 19

what happens in evolution to extra gene copies

Answer 19

Question 20

gene duplication

Answer 20

Question 21

crossing over event question

Answer 21

Question 22

how did inheritance work prior to mendel

Answer 22

blending inheritance: one short parent and one tall parent equal medium size kid (wrong)

Question 23

particulate interitance

Answer 23

you can cross 2 things and get a dominant and cross them again and get a dominant because there are always recessive genes that can come up in a generation

Question 24

polygenic

Answer 24

governed by many separate loci

Question 25

traits may be:

Answer 25

monogenic (encoded by single loci) or
polygenic (encoded by multiple loci)

traits encoded by one or very few loci are simple/mendelian
traits encoded by several loci are complex/qualitative

Question 26

monohybrid cross

Answer 26

“A monohybrid cross is the hybrid of two individuals with homozygous genotypes which result in the opposite phenotype for a certain genetic trait.” “The cross between two monohybrid traits (TT and tt) is called a Monohybrid Cross.” Monohybrid cross is responsible for the inheritance of one gene

Question 27

dihybrid cross

Answer 27

Dihybrid cross is a cross between two individuals with two observed traits that are controlled by two distinct genes

Question 28

Principle of Segregation

Answer 28

The Principle of Segregation describes how pairs of gene variants are separated into reproductive cells. The segregation of gene variants, called alleles, and their corresponding traits was first observed by Gregor Mendel in 1865. Mendel was studying genetics by performing mating crosses in pea plants. He crossed two heterozygous pea plants, which means that each plant had two different alleles at a particular genetic position. He discovered that the traits in the offspring of his crosses did not always match the traits in the parental plants. This meant that the pair of alleles encoding the traits in each parental plant had separated or segregated from one another during the formation of the reproductive cells. From his data, Mendel formulated the Principle of Segregation. We now know that the segregation of genes occurs during meiosis in eukaryotes, which is a process that produces reproductive cells called gametes.