M4.1 - Learnsmart

At the molecular level, the sequence of bases of one homolog usually differs by less than __% from that of the other homolog

1

What's the outcome of meiosis I in humans? 2n -->

1n

What is the starting material of meiosis II in humans?

23 dyads

A normal human somatic cell carries _____ pairs of chromosomes for a total of _____

23, 46

In humans, a diploid cell contains two sets of chromosomes, for a total of ___ chromosomes. In contrast, a gamete contains only a single set, consisting of ___ chromosomes.

23, 46

What's the outcome of mitosis and cytokinesis in human somatic cells? 2n -->

2n

After mitotic division is complete, a daughter cell has 40 chromosomes. What describes the chromosome composition of the mother cell in the G2 phase? ____ chromosomes, each consisting of [one/two] chromatids

40, two

___________ are different versions of the same gene

Alleles

____________ microtubules: important for the positioning of the spindle apparatus within the cell

Aster

What are the two major components of a chromosome?

DNA and proteins

A cell, such as most nerve cells in an adult mammal that will never divide again, is in the ____ phase

G0

The meaning of the term 'chromosome' can differ depending on the stage of the cell cycle we are observing. During ____ of interphase and early stages of M phase, a chromosome refers to a pair of sister chromatids (a dyad). However, at the end of M phase and during ____ of interphase, a chromosome refers to a monad which contains the equivalent of one chromatid.

G2, G1

Look at the difference between homologous chromosomes and sister chromatids Sister chromatids are formed after the homologous chromosomes are replicated

Got it

____________ microtubules: help separate the two sister chromatids from each other

Kinetochore

Which organelles contain their own DNA?

Mitochondria, chloroplasts

____________ microtubules: help push the two ends of the cell away from each other

Polar

T/F: Both synapsis and crossing over occur in prophase I of meiosis

True

T/F: Fungi, plants and protists are eukaryotes Bacteria and archaea are non-eukaryotic

True

The _______________ is an organelle at the tip of a sperm which contains digestive enzymes used to penetrate the egg's outer layers

acrosome

Bacterium reproduce asexually by a process known as __________ __________

binary fission

Each centrosome of an animal cell contains a pair of ______________ at right angles to each other

centrioles

The two chromatids of a chromosome are joined together at a region of DNA called the _________________

centromere

The two microtubule-organizing centers (MTOCs) that form the mitotic spindle of animal cells are called ___________________

centrosomes

During prophase of mitosis, the nuclear membrane breaks down into small vesicles and the nucleolus becomes less visible. Furthermore, the two ___________________ move apart from each other and the mitotic ___________ begins to form

centrosomes, spindle

The structure that is formed during crossing over is called a ______________, because it looks like the Greek letter chi, X

chiasma

Prophase The ______________ become condensed The _________________ becomes less visible The ______________ _________ begins to form The ______________ ________________ begins to dissociate into small vesicles

chromatids, nucleolus, mitotic spindle, nuclear membrane

In animal cells, cytokinesis is accomplished by the formation of a _______________ ________________ composed of __________ filaments

cleavage furrow, actin

The field of genetics that involves the microscopic examination of chromosomes is called ____________________

cytogenetics

Species that produce two morphologically different types of sex cells are said to be _____________________

heterogamous

In a diploid cell, each member of a pair of chromosomes is called a ______________

homolog

In eukaryotes, an __________________ species is one which produces gametes that are morphologically similar

isogamous

During anaphase, the chromosomes move toward the pole to which they are attached. This movement is caused by the shortening of the _________________ ________________.

kinetochore microtubules

The position of a gene on a chromosome, such as gene A in the image, is called its ____________

locus

In ______________ of meiosis, the bivalents (which are also termed tetrads) are aligned along the center of the cell

metaphase I

In meiosis, crossing over refers to the physical exchange of pieces between ___________________ of ______________________

non-sister chromatids, homologous chromosomes

The ______________ of a prokaryotic cell is the region of the cytoplasm that contains the chromosome

nucleioid

In human females, the _____________ ___________ are produced before birth. However, they enter a dormant stage at prophase of meiosis I, and remain there until the female becomes sexually mature

primary oocytes

Organisms whose chromosomes are not contained within a membrane-bound nucleus are called __________________

prokaryotes

During _______________, pairs of sister chromatids become attached to kinetochore microtubules which emanate from opposite poles of the cell

prometaphase

During ____________________ of meiosis, the spindle apparatus is complete and the chromatids are attached via kinetochore microtubules

prometaphase I

In mitosis , the _________________ point is the time in the G1 phase at which the cell becomes "committed" to the cell cycle

restriction

What does a haploid cell contain? A single [set/pair] of chromosomes

set The term "set of chromosome" refers to ploidy number. ... In humans, each set of chromosome is made of 23 chromosomes (22 autosomes and 1 sex chromosome). A pair of chromosome refers to the two homologous chromosomes in a diploid individual

During prophase of meiosis I, homologous chromosomes recognize and begin to align with each other via a process called ______________

synapsis

A bivalent is also called a _________ because it is composed of four chromosomes

tetrad

Mitosis produces [two/four] [haploid/diploid] daughter cells, while meiosis produces [two/four] [haploid/diploid] daughter cells

two diploid, four haploid

A diploid cell is defined as a cell that has [one/two] [sets/pairs] of chromosomes

two sets

If the original diploid mother cell had eight chromosomes, a cell in telophase of mitosis would have ______ nuclei, each with __________ chromosomes

two, eight

Mitosis and cytokinesis result in the formation of ____ genetically _____________ daughter cells

two, identical