WH meiosis and Genetics

Question 0

Haploid

Answer 0

N, one half set of chromosomes

Question 1

Diploid

Answer 1

2N, where cells have 2 full sets of chromosomes

Question 2

Autosomes

Answer 2

Non-sex chromosomes

Question 3

Sex chromosomes

Answer 3

X and Y chromosomes that decide sex

Question 4

Mono hybrid cross

Answer 4

Cross for ONE trait

Question 5

Dihybrid cross

Answer 5

Cross examining two traits

Question 6

Homologous chromosomes

Answer 6

Chromosome pairs that are similiar but not identical. Each carries the same genes in the same order, but the alleles for each trait may not be the same. One chromosome of each homologous pair comes from the mother and one comes from the father.

Question 7

Meiosis

Answer 7

Produces cells with half the number of original chromosomes so that two cells can combine to create offspring with a complete number of chromosomes

Question 8

Prophase I

Answer 8

Chromatin condenses, homologous chromosomes come together and intertwine in synapsis. Each pair contains four chromatids- called a tetrad. Crossing over occurs

Question 9

Tetrad

Answer 9

Pairs of attached homologous chromosomes

Question 10

Crossing over

Answer 10

Chromatids of homologous chromosomes break off and exchange equivalent pieces of DNA

Question 11

Chiasmata

Answer 11

Where chromosomes remain joined after crossing over

Question 12

Metaphase I

Answer 12

Homologous pairs align at equatorial plane and attaches to spindle fibre

Question 13

Anaphase I

Answer 13

Homologous pairs deprecate and are pulled to opposite poles, called disjunction.

Question 14

Disjunction

Answer 14

Separation of homologous chromosomes

Question 15

Telophase I

Answer 15

Mem brain forms around each nucleus. Each chromosome has sister chromosomes joined at centromere. Cell devises into two daughter cells with haploid chromosome number

Question 16

Prophase II

Answer 16

Centrioles move to opposite poles and spindle forms

Question 17

Metaphase II

Answer 17

Chromosomes migrate to opposite poles and the spindle fibre forms, chromosomes are separated into sister chromatids

Question 18

Anaphase II

Answer 18

Sister chromatids are pulled to opposite poles by spindle fibers

Question 19

Telophase II

Answer 19

A nuclear membrane forms around each haploid nucleus. Cytokinesis occurs and two daughter cells are formed, completing four haploid cells

Question 20

Increasing variation

Answer 20

Ways of increasing genetic variation:

• horizontal transfer: can move genetic material between bacteria.
• crossing over
• random assortment
• random fertilization

Question 21

Law of segregation

Answer 21

Two alleles for a heritable character segregate independently during gamete formation and end up in different gametes

Question 22

Law of independent assortment

Answer 22

Two or more genes assort independently during gamete formation. Only applies to genes located on different chromosomes

Question 23

Complete dominance

Answer 23

Ex: Classic crosses. One trait is completley dominant over another

Question 24

Incomplete dominance

Answer 24

Ex: red and white snapdragons make pink - the phenotype is in between parental varieties

Question 25

Co dominance

Answer 25

both alleles affect phenotype in desperate distinguishable ways

Question 26

Pleiotrophy

Answer 26

Genes with multiple phenotypic effects.

Question 27

Epistasis

Answer 27

Expression of a gene at one locus alters that at a second locus

Question 28

Polygenic inheritance

Answer 28

Inherited charecters that vary in gradients along a continum - there is not one specific determined expression . Caused by two or more genes

Question 29

Multiple alleles

Answer 29

When there's more than 2 different alleles for a possible phenotype

Question 30

Pedigree analysis

Answer 30

A tree diagram that shows traits across generations. Mendelian genetics can be applied to the pedigree to understand trait inheritance

Question 31

Chromosome mutations

Answer 31

Nondisjunction resulting in aneuploidy- too many or too few chromosomes

Question 32

Non disjunction

Answer 32

Mishaps in meiotic spindle chromosome distribution. One gamete received two of the same chromosome the other receives none

Question 33

Aneuploidy

Answer 33

When a gamete has abnormal chromosome number

Question 34

Monosomic

Answer 34

When a gamete has no copy of a particular chromosome it leads to a missing chromosome in the zygote. 2N-1

Question 35

Triatomic

Answer 35

When there is two of one chromosome in a zygote - 2n + 1

Question 36

Polyploidy

Answer 36

When an organism has more than 2 complete sets of chromosomes

Question 37

Gene mapping

Answer 37

Mapping where on each chromosome different genes lie

Question 38

Chromosome breakage

Answer 38

Chromosome structure changes

Question 39

Deletion

Answer 39

When a fragment of a chromosome is lost

Question 40

Duplication

Answer 40

When a deleted fragment becomes attached as an extra segment to a sister chromatid. It can also attach to a non sister chromatid which results in non identical segments

Question 41

Inversion

Answer 41

When a chromosomal fragment reattaches to the original chromosome in reverse orientation

Question 42

Translocation

Answer 42

When a fragment joins a homologous chromosome. Least harmful