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154 terms

Chapter 9-10

Oses
STUDY
PLAY
What is the fate of mRNA synthesized in the nucleus of the cell?
It leaves the nucleus.
The mRNA carries the genetic message from DNA to the _______.
cytoplasm
Once in the cytoplasm, an mRNA molecule attaches to a _____.
ribosome
Once the mRNA attaches to the ribosome, it ____.
is read to attach amino acids to eachother
As part of protein synthesis, the message on the DNA molecule is ____________.
copied onto an mRNA molecule for the next activity
Which part of the DNA molecule contains the genetic information used to make proteins?
the sequence of nucleotide bases
The sequence of nucleotide bases carries
genetic info
The first step in protein synthesis involves _______.
A section of the DNA molecule unwinds.
What kind of information is carried in the genome of DNA in a cell?
the sequence of amino acids in a protein
The general shape of the DNA molecule is a _______.
spiral staircase
The study of physical inheritance of characteristics is called ___________.
genetics
The human genome is estimated to include __________________ genes.
20,000 to 25,000
What is the molecule responsible for transmitting genetic material across generations?
DNA
What is the "Code Of Life"
DNA
What is the relationship between the sequence of bases on a molecule of DNA and the proteins in a given cell?
The bases on DNA are the code to produce proteins.
What is the correct sequence from genetic information to protein?
DNA → mRNA → ribosome → protein
The complete collection of an organism's genetic information is known as its_______.
genome
Where are the instructions for producing enzymes located?
the genome of the cell
What is contained in an organism's genome?
the total genetic information for that organism
The relationship between a blueprint and a building is analogous to the relationship between _______.
a genome and an organism
Which of the following processes most directly accounts for the increase in size as a baby grows, the growth and development of an acorn into an oak tree, and the healing of a wound?
mitosis
In the life of a cell, the process of replication refers to the ____________.
production of duplicate molecules of DNA
_______ is process of producing new DNA molecules.
Replication
During the life of a cell, the process of cytokinesis refers to _________.
division of the cytoplasm of one cell into two cells
Cytokinesis occurs at the ___ of mitosis, or cell division.
end
During the replication of a DNA molecule, which elements of DNA join to turn a single strand into a double strand?
nucleotide bases
Which of these statements is true regarding cell division in the body of a growing teenaged human?
Only a subset of cells is dividing at this point.
Dividing cells must copy their DNA, known as _______, segregate DNA and other cellular components during________, and finally split apart during __________.
replication; mitosis; cytokinesis
Of what biological molecules are chromosomes made?
DNA and protein
During which phase of the cell cycle does DNA replication occur?
S Phase
The disorganized strands of darkly staining material in the nucleus of a cell are called _________.
chromatin
How many chromosomes are found in most human cells?
46
Chromatin is produced by DNA molecules wrapping around _____________ molecules.
protein
You inherit one-half of each chromosome pair from one of your parents. These chromosomes in a chromosome pair are referred to as _________.
homologous chromosomes
What is a karyotype?
a picture of a full set of chromosomes
The cells in a human female have what composition for their sex chromosomes?
two X chromosomes
The cells of a human male have which composition for their sex chromosomes?
one X and one Y chromosome
What is an autosome?
any chromosome except a sex chromosome
What happens to the cell's chromosomes after cell division is complete?
They return a relatively formless state.
Which of the following statements about one cell cycle is true?
Mitosis precedes cytokinesis.
During the _____, we would expect to find the amount of DNA increasing from the minimum.
S phase
If a cell is no longer undergoing cell divisions (for example, a neuron) it is said to be in which phase?
G0 phase
In what form does the DNA in your cells exist?
as a dense package of DNA and protein called chromosomes
Our chromosomes exist as many sets of similar pairs, with the EXCEPTION of our______.
sex chromosomes
The period during which a cell replicates its DNA is known as the _______.
S Phase
Which of the following items would you expect to find in a chromosome?
DNA and protein
During ___ we would find the least amount of DNA, because DNA replication has not yet occurred.
G1
__ cell division, the blueprint (DNA) is copied, but ___ cell division, the parts (organelles) of the cell are divided between the two daughter cells.
Before;during
Which stage of mitosis involves a separation of sister chromatids?
anaphase
The cell cycle is what dictates when a cell should divide. If you were to remove limits on the cell cycle in certain cells, what would you expect the outcome to be?
cancerous cells
If you were to remove the centrosomes from a cell, what do you think that would do to mitosis?
It would prevent chromosomes from segregating properly.
Which of the following would you expect to occur during telophase of mitosis?
Nuclear membrane begins to re-form.
If a cell has 10 chromosomes, how many chromosomes will be present in each of the daughter cells after mitosis?
10
A human cell fails to undergo cytokinesis while performing mitosis. How many chromosomes will be in the resulting cell?
92 (twice as many chromosomes)
Why are checkpoints needed in mitosis?
to regulate cell division
Which is the initial phase of mitosis?
prophase
A contractile ring of protein filaments is characteristic of which phase of cell division?
cytokinesis
During which phase of mitosis would you expect to see chromosomes lined up in the middle of the cell?
metaphase
In which stage of mitosis does cytokinesis begin?
anaphase
The correct order of mitosis is______.
prophase, metaphase, anaphase, telophase
Which of the following phases of the cell cycle is the longest, in terms of time, for a typical cell?
interphase
A circular chromosome is typically found in ______.
bacteria
In plants, the formation of the cell plate occurs during _________.
cytokinesis
Bacteria divide by ________.
binary fission
What is the first step of bacterial replication?
DNA replication
Plant cell mitosis is basically like animal cell mitosis EXCEPT that _________
plant cells use a cell plate to separate daughter cells
What is different about the DNA in bacterial cells compared with the DNA in eukaryotic cells?
Bacterial DNA is circular, whereas eukaryotic DNA is linear.
What is the main difference between animal and plant cell divisions?
Plants have to replicate a cell wall as well.
Cell division in bacteria is known as____.
binary fission
If a cell has a diploid number of 10 (2n = 10), how many chromosomes will be present in each daughter cell at the end of meiosis?
5
_____ creates haploid daughter cells.
Meiosis
If an organism's somatic cells contain 50 chromosomes, how many chromosomes would you expect to find in its gametes?
25
____ contain half the number of chromosomes that a somatic cell contains.
Gametes
Which of the following statements about the products of a single cell that has gone through meiosis is true?
The daughter cells are haploid.
Which of the following statements about gametes is FALSE?
Gametes are diploid.
An organism that reproduces sexually, such as a human, must produce cells that are _____.
haploid
Haploid cells can combine to make a ____ cell.
diploid
Which of the following statements about the products of a single cell that has gone through meiosis is true?
The daughter cells are haploid.
A human cell fails to undergo cytokinesis while performing meiosis I, so that the daughter cells do not form. How many chromosomes will be in each resulting cell?
46
Each daughter cell should have __ chromosomes.
23
In what phase of meiosis would you expect to see crossing over occur?
prophase I
A cell contains 16 chromosomes at the end of prophase I. How many chromosomes will be in each daughter cell at the end of prophase II?
8
If the starting diploid number is 16, the cells at the end of meiosis I will have _____ that number.
half
Chromosomes are not paired in _____.
meiosis II
The cells at the end of meiosis I are NOT ready to function as gametes. Why not?
They are haploid, but the chromosomes are still in duplicated form.
Horses have a diploid number of 64, and donkeys have a diploid number of 62. A mule is the result of fertilization between a horse gamete and a donkey gamete. What is the mule's chromosome number?
63
Which of the following statements about meiosis is true?
Meiosis shuffles alleles and creates chromosomes that are genetically different from the parent's chromosomes.
During which type(s) of cell division does a ring of contractile microfilaments form a cleavage furrow around the equator of the cell?
mitosis and meiosis I and II
Which type(s) of cell division are immediately preceded by replication of DNA?
meiosis I and mitosis only
The important process of crossing over occurs during which stage of meiosis?
prophase I
When you examine a cell under a microscope, you see that the nucleus is NOT present and that the chromosomes are condensed and lined up singly in the center of the cell. In what stages of division might this cell be?
metaphase of mitosis or meiosis II
If a daughter cell contains 14 chromosomes at the end of meiosis I, how many chromosomes will each daughter cell contain at the end of meiosis II?
14
The daughter cells at the end of meiosis I and II have the _____ chromosome number.
same
Which of these events occurs in meiosis but NOT in mitosis?
recombination
In prophase I ____ occurs, and in metaphase I ________ occurs
crossing over;independent assortment
If a sperm cell contains 16 chromosomes, the original parent cell that started meiosis must have contained ____ chromosomes.
32
During which type(s) of cell division would you expect to see both tetrads and recombination?
meiosis I only
During which type(s) of cell division does the DNA begin to condense into visible chromosomes, the nuclear membrane breaks apart into small vesicles, nucleoli disappear, and chromosomes are composed of two chromatids?
meiosis I and mitosis only
If a daughter cell contains six chromosomes at the end of meiosis I, how many chromosomes will each of the daughter cells contain at the end of meiosis II?
6
The daughter cells at the end of meiosis II will have the ______ of chromosomes as the daughter cells at the end of meiosis I.
same number
Crossing over occurs during ___________, and it is important because it ___________.
prophase I; generates diversity
Which of the following processes leads to genetic diversity?
recombination
Recombination is_______.
the swapping of DNA between homologous chromosomes
If crossing over were to be prevented in a species, what would the consequences be?
The genetic diversity of that species would be reduced.
If each chromosome can sort independently of other ones, you would have a _______.
random mix
Recombination is_______.
the swapping of DNA between homologous chromosomes
The exchange of genetic material between homologous chromosomes that leads to new combinations of genetic material during meiosis is called ________.
crossing over
Aside from crossing over, how many different chromosome combinations in a gamete can a human make?
8.4 million
An allele on the Y chromosome controls the development of a rare genetic disease. A man with this rare disease has three children. The first two are daughters without the disease. What is the probability that the third child, a son, will have the disease?
100%
All egg cells contain an X chromosome. This does ___ determine the ___ of the offspring
not;sex
Sex is determined by the male gamete, which can be carrying either an X or Y chromosome. Thus, there is a ___ chance that it is a girl. Previous offspring have no effect on this outcome.
1/2
A gamete from a human female contains _______.
22 autosomes and an X chromosome
Where do all the first organelles come from in a new zygote?
from the egg
Where does meiosis occur in humans?
in specialized cells called primary spermatocytes and primary oocytes
Why do primary and secondary oocytes divide asymmetrically?
to produce one highly enriched egg
What features are associated with mature human sperm?
a nucleus with 22 autosomes and an X or Y chromosome, mitochondria, flagellum
Which of the following statements concerning human spermatogenesis is correct?
Spermatids are the only cells in the human body that possess flagella.
The Y chromosome can be used to trace a person's lineage many generations into the past. What characteristic of the Y chromosome makes that possible?
The Y chromosome does not engage in crossing over.
Which of the following is a type of sexual reproduction?
self-fertilizing flowers
What is the correct order for spermatogenesis?
spermatogonium → primary spermatocyte → secondary spermatocyte → spermatids
One spermatogonium can produce __ spermatid(s), and one oogonium can produce __ egg(s).
4; 1
What is the genetic disadvantage of asexual reproduction?
There is never a new combination of genes.
What is a hermaphrodite?
an organism with both male and female reproductive elements
Genes are composed of sequences of ______, which act as the molecular code for proteins.
bases
Genes contain the information for which of the following processes?
All of these are controlled by DNA.
In a molecule of DNA, the phosphate-sugar connections are the __________, whereas the bases are the _________.
backbone; information
Where do all cells come from?
They are the result of the division of previously existing cells.
What happens at the end of DNA replication? _________.
Two strands of DNA are produced.
Which of the following statements about homologous chromosomes is true?
The father donated one of each pair of homologous chromosomes, and the mother donated the other.
Each individual chromosome at the beginning of mitosis is composed of _______.
two sister chromatids
Replication of the original chromosomes occurs during which stage of the cell cycle?
during the S stage
Which of the following lists represents the correct order of events in the cell cycle?
metaphase, anaphase, telophase, interphase, prophase
Which of the following statements about mitosis is correct?
It produces daughter cells with the same number of chromosomes as the original parent cell.
Chromosomes line up in the middle of the cell during which stage of the mitosis?
metaphase
Spindle fibers first appear during which stage of mitosis?
prophase
Which of the following occurs during prophase of mitosis?
Centrosomes separate and move to opposite poles of the cell.
During which phase of mitosis does the chromatin begin to condense to form the chromosomes?
prophase
Compared with eukaryotic cell division, bacterial cell division is ________.
simpler than eukaryotic cell division
Which of the following statements about binary fission in a bacterial cell is true?
A bacterium produces an extra copy of its chromosome before it divides by binary fission.
Cells produced by meiosis are called _________.
gametes
Gametes are ______, whereas somatic cells are_______.
sex cells; all other cells
A certain type of somatic cell contains 58 chromosomes. How many chromosomes would you expect a gamete of this organism to contain?
29 chromosomes
In meiosis, the chromosome number of each of the daughter cells will be _____________ the chromosome number of the parent cell.
exactly half as many as
When a pair of sister chromatids pairs up with its homologous set of chromatids, what is the result called?
a tetrad
The end product of meiosis is ___ cells that are ____.
four; haploid
How are meiosis and mitosis similar?
Both are preceded by duplication of DNA.
At which stage during meiosis are sister chromatids separated into two different groups of chromosomes?
anaphase II
How do mitosis and meiosis differ from each other?
The cells formed by mitosis are diploid, whereas the cells formed by meiosis are haploid.
Which of the following definitions for crossing over is accurate?
Genes on the paternal chromosome are traded for the same genes on the maternal chromosome.
What is the purpose of recombination (crossing over)?
to create chromosomes that are a new combination of paternal and maternal material
Autosomes are ____________.
all chromosomes other than the X and Y
Given what you know about meiosis, where do human males get their X chromosome?
always from the mother
Male humans have a(an) _______capacity to produce sperm, and female humans have a(an)______capacity to produce eggs.
unlimited; fixed
Binary fission, vegetative reproduction, and regeneration are all examples of _____.
asexual reproduction