Cell Division - The Cell Cycle

Question 1

what happens to a cells cytoplasm as the cell grows in size

Answer 1

the volume of its cytoplasm increases at a faster rate than the surface area of its plasma membrane

Question 2

who was the first scientist to publish a conclusion about how living cells originate and when

Answer 2

rudolph virchow in 1855

Question 3

what was rudolph virchows conclusion

Answer 3

that new cells arise only from the division of cells

Question 4

define cell cycle

Answer 4

a continuous sequence of cell growth and division/the life cycle of a cell

Question 5

whats a somatic cell

Answer 5

any of the cells in a multicellular organism except those that form gametes

Question 6

who made the first accurate description of the cell cycle, when and what did he name it

Answer 6

walther flemming in 1897; mitosis

Question 7

what determines the structure and function of a cell

Answer 7

its genetic material

Question 8

what is the central feature of the cell cycle

Answer 8

the way that genetic material is duplicated and then passed from the original cell to each new cell

Question 9

define parent cell

Answer 9

the original cell that divides to produce two new daughter cells during cell division

Question 10

define daughter cell

Answer 10

any one of two cells produced from the division of a parent cell

Question 11

define chromosome

Answer 11

a length of DNA and its associated proteins that is found in the nucleous of eukaryotic cells

Question 12

define eukaryotic cells

Answer 12

cells with a membrane-bound nucleous that make up protists, fungi plants and animals

Question 13

define histones

Answer 13

protein found in chromosomes that acts as a scaffold around which DNA winds, allowing it to become more compact

Question 14

define chromatin

Answer 14

long fibres that form chromosomes and contain DNA, a small amount of RNA and various proteins

Question 15

true or false: chromatin is condensed

Answer 15

false; they are a non-condensed form of genetic material that predominates for most of the cell cycle

Question 16

whats a centromere

Answer 16

the point at which two sister chromatids of a chromosome are joined and to which the spindle fibres are attached during mitosis

Question 17

what is the pinched in region of a condensed chromosome called

Answer 17

the centromere

Question 18

what are the 4 levels of genetic organization

Answer 18

1. the DNA molecule winds around histones to form a bead-like structure
2. the bead-like structure forms a tightly packed array to produce strands of chromatin
3. chromatin fibres form loops which are attached to a supporting protein scaffold
4. the scaffold folds further to condense the genetic material into chromosomes, duplicates during replication, forming identical chromosomes joined by a centromere

Question 19

how many chromosomes do human somatic cells have

Answer 19

46 chromosomes which can be organized into 22 pairs of homologous chromosomes and 2 sex chromosomes

Question 20

what is a homologous chromosome

Answer 20

chromosomes that contain the same gene sequence as another but that may not be made up of the same alleles

Question 21

what is an easy way to tell if it is a homologous chromosome

Answer 21

they will look the same

Question 22

true or false: homologous chromosomes are identical

Answer 22

false; they carry the same genes at the same location but can have different alleles of those genes so they are not identical to each other even though they appear similar

Question 23

define autosomes

Answer 23

any chromosomes other than a sex chromosome

Question 24

true or false: sex chromosomes are autosomes

Answer 24

false

Question 25

how many autosomes do human somatic cells have

Answer 25

22 pairs

Question 26

define sex chromosome

Answer 26

X or Y chromosome that carries the genes involved in determining the genetic sex of an individual

Question 27

true or false: sex chromosomes are a homologous pair

Answer 27

false; they can be a homologous pair if its female (XX) but if its a male individual then they will not be homologous (XY)

Question 28

define locus

Answer 28

a specific location on a chromosome

Question 29

define diploid

Answer 29

term describing a cell that contains two pairs of every chromosome

Question 30

how do you designate a diploid cell

Answer 30

2n

Question 31

what is the diploid number in humans

Answer 31

46

Question 32

define haploid

Answer 32

term describing a cell containing unpaired chromosomes that are half the number of chromosomes that the diploid parent cell contains

Question 33

how do you designate a haploid cell

Answer 33

as n

Question 34

what types of cells are considered haploid

Answer 34

gametes

Question 35

define polyploid

Answer 35

a term describing a cell which contains sets of more than two homologous chromosomes (ex 4n)

Question 36

what are the 3 main ways that chromosomes can be differentiated from one another

Answer 36

overall length, location of their centromere, banding pattern when stained

Question 37

what are the two main stages of the cell cycle (general)

Answer 37

a growth stage and a division stage

Question 38

which phase of the cell cycle makes up most of its life

Answer 38

the interphase

Question 39

what are the 3 phases of interphase

Answer 39

G1, S and G2

Question 40

when does interphase end

Answer 40

when the cell begins the process of nuclear division/mitosis

Question 41

whats the G1 phase

Answer 41

the first part of interphase during which cells carry out rapid growht and metabolic activity

Question 42

whats the S phase

Answer 42

the middle part of interphase during which the cell's DNA is replicated

Question 43

what happens in the S phase

Answer 43

the DNA in the chromatin replicates to create a second identical set of DNA and then the two identical chromosomes are joined together at the centromere

Question 44

what is G2

Answer 44

the last part of interphase during which the cell rebuilds its reserves of energy and manufactures proteins and other molecules to prepare for division

Question 45

whats the purpose of the G2 phase

Answer 45

to let the cell rebuild its reserves of energy to prepare for division because most of the cells energy is consumed during DNA replication in the S phase

Question 46

other than rebuilding energy, what else happens in G2

Answer 46

the cell manufactures proteins and other molecules to make structures required for the division of the nucleus

Question 47

define mitosis

Answer 47

the division of the genetic material and the contents of the cell's nucleus into two complete and separate sets, resulting in a daughter cell receiving the exact number of chromosomes and genetic make-up as the parent cell

Question 48

define cytokinesis

Answer 48

the separation of cytoplasm and organelles and the formation of two daughter cells