Topic 4-1

Question 1

what is the endosymbiotic hypothesis?

Answer 1

an ancient archaea swallowed a bacteria, which gave the rise to eukaryotes

Question 2

what evidence is there for the endosymbiotic hypothesis?

Answer 2

• mitochondira and chloroplasts have their own DNA
  -mitochondria and chloroplasts are biochemically more similar to bacteria than euk

Question 3

why are viruses not considered to be prokaryotic or eukaryotic?

Answer 3

they are too genetically different from either, and aren’t even cells

Question 4

• simple division: separation of replicated circular chromosome
• origin of replication
• high rate of replication:
  these are characteristics of:

Answer 4

binary fission (prokaryotic cell reproduction)

Question 5

cell which carries two sets of genetic information

Answer 5

diploid

Question 6

cell which carries one set of genetic information

Answer 6

haploid

Question 7

humans have _____ chromosomes and _____ pairs of homologous chromosomes

Answer 7

46, 23

Question 8

what are homologous chromosomes?

Answer 8

a set of one paternal and one maternal chromosomes that are not held together by a centromere

Question 9

what are sister chromatids?

Answer 9

a set of chromosomes that are identical (have all the same alleles) and are connected by a centromere

Question 10

what is the major concern of the G1/S checkpoint?

Answer 10

cells have the protein machinery necessary for the replication of DNA

Question 11

once the cell has passed the G1/S checkpoint, it is:

Answer 11

committed to eventual cell division

Question 12

what is the major concern of the G2/M checkpoint?

Answer 12

the cell’s DNA has been fully replicated and is undamaged

Question 13

what is the major concern of the M checkpoint?

Answer 13

that all the spindles are correctly attached to the chromosomes

Question 14

spindle microtubules are composed of:

Answer 14

tubulin subunits

Question 15

what is the kinetochore made up of?

Answer 15

proteins that recognize the centromere of chromosomes

Question 16

what happens to chromosome fragments that lack centromeres?

Answer 16

they are not recognized by the cells, and are thus degraded

Question 17

what are the three major consequences of mitosis?

Answer 17

1) results in 2 genetically identical daughter cells
2) results in 2 daughter cells that have the full complement of chromosomes (no increase or decrease)
3) daughter cells contain half of the original cytoplasm and half of the original organelles

Question 18

forms rings at DNA replication stage

Answer 18

cohesins

Question 19

cleaves cohesin subunits during anaphase

Answer 19

separase