Exam 4 part 5

Question 1

What cell cycle checkpoint most frequently fails in cancerous cells

Answer 1

G1

Question 2

How do malignant cells travel through the body

Answer 2

Lymphatic and circulatory systems

Question 3

What protein actually triggers the production of S-phase proteins

Answer 3

E2F

Question 4

What are the components of an organism’s karyotype

Answer 4

Number of chromosomes the type of chromosomes that a particular organism has

Question 5

What is the relationship between homologous chromosomes and alleles

Answer 5

Alleles are gene that are encoding same trait, homologous is one from mom one from dad

Question 6

What does the term “ploidy” mean

Answer 6

How many copies of chromosomes

Question 7

Describe the main difference between Meiosis I and Meiosis II

Answer 7

In Meiosis I, homologs split

In meiosis II, sister chromatids separate

Question 8

What splits when homologs split during Meiosis 1

Answer 8

Synaptonemal complex

Question 9

When sister chromatids separate in Meiosis II, what is splitting apart

Answer 9

cohesions

Question 10

What is forming when you see the Chiasma? What is occurring here

Answer 10

Tetrad (or bivalent)

Crossing over occurs

Question 11

Why are you haploid at the end of Meiosis I

Answer 11

Because Meiosis I is when you are doing the reductive division; goes from diploid to haploid
Daughter cells now only have 1 copy of each homologous chromosome

Question 12

Why are you still haploid at the end of Meiosis II

Answer 12

Because all you did in Meiosis II is break apart the sister chromatids

Question 13

What is produced through asexual reproduction

Answer 13

clones

Question 14

What causes genetic variation in sexual reproduction?

Answer 14

Independent assortment, crossing over and outcrossing

Question 15

Independent assortment

Answer 15

you never know what side of Metaphase plate the homologous chromosomes will end up on. Separation and distribution of homologous chromosomes during Meiosis I can result in a variety of combinations of maternal and paternal chromosomes

Question 16

Crossing over

Answer 16

new combinations of alleles on the same chromosomes; combinations that did not exist in each parent

Question 17

Outcrossing

Answer 17

during fertilization; gametes from two different individuals combine to form offspring

Question 18

How is it possible for an organism that self-fertilizes itself to produce offspring that are genetically different

Answer 18

Still 2 copies of each chromosome so they can line up differently and be split up differently
So they can still do crossing over and independent assortment

Question 19

If homologs or sister chromatids don’t separate completely, what is this mistake called

Answer 19

Nondisjunction

Question 20

What does nondisjunction result in

Answer 20

Aneuploid zygotes which means too few or too many chromosomes. typically dont survive to produce viable offspring

Question 21

How common is nondisjuction

Answer 21

happens in as many as 10 percent of meiotic divisions

Question 22

what is down syndrome an example of

Answer 22

trisomy

Question 23

Down’s syndrome occurs due to nondisjunction during Meiosis I, a result in the failure in the breakdown of what

Answer 23

Synaptonemal complex

Question 24

Why would males be considered a disadvantage of sexual reproduction

Answer 24

Males do not directly reproduce

Question 25

What is the Purifying Selective Hypothesis

Answer 25

Anything that compromises your fitness is removed through the process of purifying selection
Natural selection against deleterious alleles

Question 26

What is the Changing-Environment hypothesis

Answer 26

Offspring that are produced by sexual reproduction are more likely to survive and produce offspring if the environment changes
Sexually produced offspring can evolve quicker

Question 27

What plant did he use for his experiments

Answer 27

common garden peas

Question 28

Describe blending inheritance vs. inheritance of acquired characteristics

Answer 28

Blending: parental traits blend such that their offspring have intermediate traits
Acquired characteristics: parental traits are modified then passed on to their offspring

Question 29

What characteristics do model systems usually have

Answer 29

Easy to grow
Reproductive cycle is short 
Produces large numbers of seeds
Matings are easy to control 
Traits are easily recognizable

Question 30

How did Mendel arrange matings

Answer 30

Mendel prevented self-fertilization by removing male reproductive organs
Then he used pollen from other plants to fertilize these flowers thereby performing cross-fertilization

Question 31

What traits did Mendel look at in the peas

Answer 31

Seed shape 
Seed color 
Pod shape 
Flower color 
Flower and pod position 
Stem length