Biology - The Cellular Basis of Reproduction and Inheritance

this is the biological process by which new organisms are produced:

reproduction

organisms can reproduce *___ or* __

asexually, sexually

asexual reproduction is:

a cloning process

hereditary material is found:

in the DNA located in a chromosome

the process of _____ allows organisms to reproduce asexually:

mitosis

mitosis involves the division of what into what?

one cell into two identical daughter cells

does mitosis conserve chromosome number?

yes

mitosis occurs when:

multi-cellular organisms grow, damaged cells are replaced, single-celled organisms make new organisms.

bacterial cell division is called:

binary fission

the time the parent cell is formed to the division of the two cells is called the:

cell cycle

the cell cycle is comprised of these phases:

G1, S, G2, M, C

interphase is made up of:

G1, S, G2

Interphase accounts for ___% of the cell cycle.

90

Interphase is a time of _______:

high metabolic activity

In G1, what happens?

the cell grows by producing proteins and organelles.

In S, what happens?

DNA replication occurs, forms 2 sister chromatids out of each chromosome

In G2, what happens?

the nuclear envelope forms, 2 centrosomes are formed from replication.

cell division includes 2 processes:

mitosis and cytokinesis

mitosis is division of the ___, but cytokinesis is division of the _____.

nucleus, cytoplasm

what are the five phases of mitosis?

prophase, prometaphase, metaphase, anaphase, telophase

in prophase, what happens?

nucleolus disappears, chromosomes are visible and duplicated chromosomes join together at the centromere (makes 2 sister chromatids), early mitotic spindle begins to form, centrosomes move away from each other.

this is the specialized region where duplicated chromosomes are connected:

centromere

the mitotic spindle is made up of what?

microtubules and the 2 centrosomes

Arrays of short microtubules that extend from the centrosomes are called:

asters

in prometaphase, what happens?

the nuclear envelope fragments, centrosomes move away from each other, kinetochore microtubules connect to the kinetochores of the chromosomes, while nonkinetochore microtubules interact with microtubules from the opposite pole.

a special protein structure in the centromere is called the:

kinetochore

what is the longest stage of mitosis?

metaphase at 20 minutes

what happens in metaphase?

the chromosomes lie along the metaphase plate with their centromeres on the equator, the centrosomes are on opposite sides of the cell

what is the shortest phase of mitosis?

anaphase at a few minutes

what happens in anaphase?

2 sister chromatids seperate to become daughter chromosomes, kinetochore microtubules shorten as the daughter chromosomes move to the ends of the cell, nonkinetochore microtubules elongate

what happens in telophase?

mitosis is completed, 2 daughter nuclei begin to form, 2 nuclear envelopes form around the chromosomes, 2 nucleoli begin to form, chromosomes become less dense

In animal cells, cytokinesis begins with the formation of:

a cleavage furrow

these pinch the animal cell to create 2 daughter cells:

actin microfilaments

describe plant cytokinesis:

vesicles form the cell plate which creates 2 plasma membranes. these 2 membranes fuse with the outer membrane, creating the daughter cells. cellulose is added to the middle lamella to create a new cell wall.

each chromosome has ___ DNA molecule:

1

humans have __ chromosomes in almost all of their cells:

46

a DNA molecule is a:

double helix structure

Each nucleotide is made up of:

a phosphate group, a pentose sugar, and a nitrogen base

The DNA nucleotides differ only in the:

nitrogen bases

These single ringed structures are called:

pyrimidines

pyrimidines include:

thymine and cytosine

six–membered ring fused to a five– membered ring are called:

purines

purines include:

adenine and guanine

what are the DNA nucleotide pairs?

A and T, C and G

Chromosomes are electronically arranged in pairs, starting with the longest. This ordered display is called a:

karyotype

Images of chromosomes are best obtained during:

metaphase

Homologous chromosomes have the same:

length, centromere position, and staining pattern

Human females have what XY chromosomes?

XX

Human males have what XY chromosomes?

XY

XY chromosomes are called:

sex chromosomes

All other chromosomes are called:

autosomes

We inherit what from each parent?

one chromosome pair

Cells with 2 chromosomes sets are called:

diploid cells

haploid number:

n

diploid number:

2n

which human cells are haploid cells?

gametes (eggs and sperm)

another word for eggs is:

ovum

Each chromosome consists of:

2 sister chromatids

any two chromatids in a pair of homologous chromosomes that are not sister chromatids are called:

nonsister chromatids

the union of gametes, culminating in fusion of their nuclei, is called:

fertilization

The resulting fertilized egg:

zygote

is the zygote diploid or haploid?

diploid

which phase of mitosis is this?

interphase

what phase of mitosis is this?

prophase

what phase of mitosis is this?

prometaphase

what phase of mitosis is this?

metaphase

what phase of mitosis is this?

anaphase

what phase of mitosis is this?

telophase

what phase of mitosis is this?

cytokinesis

The only cells of the human body not produced by mitosis are:

gametes

the 2 stages of meiosis are:

meiosis 1 and meiosis 2

in meiosis 1, what is seperated?

the homologous chromosomes

in meiosis 2, what is seperated?

the sister chromatids

this is the longest phase of meiosis:

prophase 1

what happens in prophase 1?

nucleolus disappears, mitotic spindle begins to form, chromosomes condense and become visible, sister chromatids formed, centrosomes move away from each other, homologous chromosomes connect to form the synaptonemal complex. this is called synapsis. when pieces of the chromosomes break, they exchange DNA in regions called the chiasmata, nuclear envelope fragments, synaptonemal complex disassembles in late prophase. kinetochores of chromosomes attach to microtubules.

what phase of meiosis is this?

prophase 1

what happens in metaphase 1?

the centrosomes are on either side of the cell, the tetrads lie along the metaphase plate, the homologous chromosomes are attached to kinetochore microtubules.

what phase of meiosis is this?

metaphase 1

what happens in anaphase 1?

the 2 homologous chromosomes begin to seperate, they move to opposite ends of the cell, the kinetochore microtubules shorten while the nonkinetochore microtubules elongate.

what phase of meiosis is this?

anaphase 1

what happens in telophase 1 and cytokinesis?

both daughter cells have a haploid set of chromosomes, each chromosome is made of 2 sister chromatids. division of the cytoplasm takes place, and it starts with the formation of the cleavage furrow, the nuclear envelope forms, and chromosomes become less condensed. this concludes meiosis 1.

what phase of meiosis is this?

telophase 1 and cytokinesis

what happens in prophase 2?

spindle begins to form, the centrosomes begin to move away from each other, chromosomes are made of two sister chromatids that may differ from each other.

what phase of meiosis is this?

prophase 2

what happens in metaphase 2?

the chromosomes lie on the metaphase plate, the kinetochore microtubules attach to the kinetochores of the chromosomes

what phase of meiosis is this?

metaphase 2

what happens in anaphase 2?

sister chromatids seperate and form daughter chromosomes, kinetochore microtubules shorten and nonkinetochore microtubules elongate.

what phase of meiosis is this?

anaphase 2

what happens in telophase 2 and cytokinesis?

nucleus and nucleolus form, chromosomes decondesend, cytokinesis occurs

what phase of meiosis is this?

telophase 2 and cytokinesis

3 mechanisms that result in genetic variation arising from sexual reproduction are:

independent assortment of chromosomes, crossing over, random fertilization

The placement of one paternal/maternal chromosome on the metaphase plate is independent of any other paternal/maternal chromosome. This is called:

independent assortment of chromosomes

Anaphase and independent assortment of chromosomes:

the homologous chromosomes separate and each pole gets some paternal and some maternal chromosomes.

how many possible combinations of chromosomes are there in human cells?

8 millions

crossing over produces what?

recombinant chromosomes that carry genes from both parents

In humans, an average of__ to __ crossover events occur per chromosome pair,

1,3

what are the number of diploid combinations that a human zygote can have?

64 trillion

The frequency of cell division varies with the:

type of cell

Which human cells divide frequently?

skin cells

Which human cells do not divide frequently?

liver cells, nerve cells, muscle cells