Quiz 3 Material

Question 1

Monoploidy

Answer 1

Only one set of chromosomes
(N)
- ex. Bees 🐝

Question 2

Polyploidy

Answer 2

-More than two sets of chromosomes
- can be triploid, tetraploid, etc.
- common in flowering plants,
- very rare in animals

Question 3

2 types of polyploids

Answer 3

Autoploids and aloploids

Question 4

Autoploids

Answer 4

• the chromosome sets are all identical
• the chromosomes are derived from the same species
• Autoploids usually have
  - more vegetative growth (larger cells, thicker leaves, bigger flowers and fruits, larger plants)
  - less seed production
  Think auto= self

Question 5

Autoplolyploidy occurs during

Answer 5

Mitosis - no cell division so 2n—-> 4n (tetraploid)
Meiosis I - nondisjunction (gametes have 2n instead of n) and when fertilized, zygotes have 3n (triploid)

Question 6

Examples of polyploid plants

Answer 6

Seedless fruits like oranges and watermelons and bananas and grapes are triploid
Strawberries are 8n and oats are 6n

Question 7

Problems with polyploidy

Answer 7

Many polyploids are sterile due to problems with pairing and separation of homologous chromosomes in meiosis
- ex. Bananas 3n attempt meiosis but just can’t/it fails
- the whole Point of sexual reproduction is that gametes are compatible and make the ploidy back when they come together
- the banana produces gametes with 2 copies of the same chromosome, some with one and others with none
- gametes that have extra chromosomes or lack certain chromosomes are not viable

Question 8

Problems with polyploidy independent assortment

Answer 8

Not all sets of chromosomes will make the same decisions, some will separate bivalent, univalent and others trivalent
The odd number makes it impossible to generate gametes that have the same number of chromosomes
There are 11 trivalents (3n) in bananas and each can separate however

Question 9

Allopolyploids

Answer 9

• • polyploids that are the result of crosses between 2 or more species (usually related/have to be similar)
• from interspecies crosses in plants

Question 10

Sterile hybrid

Answer 10

Hybrid because two different species made it
But sterile because there are no pairs of homologous chromosomes so meiosis fails
But these can still reproduce asexually/with themselves

Question 11

Fertile 4n allopolyploid

Answer 11

If mitosis fails when sterile hybrid (2n) tries to undergo citokineses
And then that failed cell goes through mitosis again! And from 2n to 4n it becomes fertile since now the chromosomes have pairs! They produce 2n gametes
Ex. Wheat! 4n=28

Question 12

Amphidiploid

Answer 12

Is another name for allotetraploid

Question 13

Polyploidy in animals

Answer 13

You don’t see it
Interspecies crosses result in sterile animal
Chromosome doubling which could potentially restore fertility doesn’t work and is not tolerated

Question 14

Aneuploidy

Answer 14

Diploid genome which lacks a chromosome or has an extra chromosome
Trisomies (extra)
Monosomies (lacking one)
Caused by nondisjunction during meiosis

Question 15

What are the sex chromosome aneuploid conditions

Answer 15

XXY Kleinfelter syndrome
XO Turner syndrome
XXX Triple X syndrome
XYY double Y males

Question 16

Prophase arrest

Answer 16

Germ cells remain in an arrested prophase I until ovulation (16 to >40yrs)

Question 17

Amphidiploid

Answer 17

Aka allotetraploid
Functional diploid
Like a fertile hybrid

Question 18

Triticale

Answer 18

Cross of wheat that has favourable high protein content and high lysine content
Ex of allotetraploid

Question 19

Chromosome deletion

Answer 19

Missing a chromosome segment
Ex. Crit dû chat syndrome

Question 20

Crit dû chat syndrome is an example of

Answer 20

Hypoploidy
Caused by a Deletion on chromosome 5

Question 21

Chromosome Duplication

Answer 21

An extra chromosome segment

Question 22

Components of a cloning plasmid

Answer 22

1) a MCS a multiple cloning site
2) An ORI an origin of replication
3) a selectable marker

Question 23

MCS

Answer 23

A multiple cloning site
A region with many restriction sites into which exogenous or external DNA is inserted

Question 24

ORI

Answer 24

An origin of replication site which enables plasmid replication in host cells

Question 25

A selectable marker

Answer 25

Antibiotic resistance gene which enables researchers to select cells that contain the plasmid

Question 26

How process of cloning plasmid

Answer 26

1. Digest- plasmid and foreign dna are created with restriction enzymes forming complementary sticky ends
2. Ligation- dna fragments and plasmid hybridize at sticky ends. Dna ligand forms phosphodiester bonds to seal nicks in each strand
3. Transformation- the lighted plasmid is mixed with bacterial cells under optimal conditions
4. Only cells containing the plasmid will grow on ampicillin plates forming colonies which all have the plasmid

Question 27

Restriction enzymes

Answer 27

A group of endonucleosomes produced in bacteria as a means of destroying foreign dna at specific double stranded sequences known as restriction sites

Question 28

Restriction sites

Answer 28

Typically 4-8 base pairs in length
Often palindromic
Where dna is cleaved by restriction enzymes

Question 29

How is dna organized in the eukaryotic cell

Answer 29

• nucleosides
• 30 nm chromatin fiber
• interphase chromosomes/ chromosome scaffold

Question 30

Robertsonian translocation

Answer 30

are formed by the fusion
of two nonhomologous
chromosomes at their
centromeres

Question 31

Robertsonian translocation

Answer 31

are formed by the fusion
of two nonhomologous
chromosomes at their
centromeres