BIO Chapter 5 - Part 1
Haploid gametes have ___ chromosomes while diploid zygote has ___ chromosomes.
23 and 46
How many individual pieces of DNA are in the nucleus of each of your body cells?
46, one long piece of DNA for each chromosome
Human white blood cells are often multinucleated. How many chromosomes would be present in a white blood cell with two nuclei?
92
When does a cell change from haploid to diploid?
After the fusion of a zygote
Why can't a plant cell pinch inward and from a cleavage furrow?
All plant cells are surrounded by a stiff cell wall that prevents pinching inward
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Anapase
When does the cell plate form during cell divison?
At the completion of plant cell mitosis
Explain why the following statement is incorrect: "During mitosis, chromosomes are duplicated and distributed."
Because the chromosomes are already duplicated (during interphase) by the time the mitotic phase starts
From a cell division perspective, why are all of the trillions of cells in your body genetically identical?
Because they all descended via cell division from a single original cell(the zygote).
What occurs in the G2 phase of interphase?
Cell resumes normal functions and synthesizes more proteins and organelles grow and divide
What events occur during prophase?
Chromosomes condense and are attached to spindle fibers, the nuclear envelope breaks down
What must happen before a cell can begin mitosis?
Chromosomes must be duplicated.
What occurs in G1 phase of interphase?
Chromosomes uncondensed, loosely arranged in nucleus; cell carries out normal activities
What occurs during telophase?
Chromsomes are unpackaged into chromatin, nuclear envelope reforms, nucleolus reappears and cytokinesis begins
At the end of the mitotic phase, the cytoplasm divides in a process called ______.
Cytokinesis
Chromosomes contain most of the cell's ____ which acts as the molecule of heredity.
DNA
How does such a large quantity of DNA fit within the nucleus of one of your cells?
DNA is associated with proteins that compact the DNA to form a package called chromatin.
What occurs in the S phase of interphase?
Each chromosome is duplicated; every chromosome in the nucleus has a duplicate, called a sister chromatid attached at the centromere
During ______, the cell carries out its normal functions and the chromosomes are thinly spread throughout the nucleus.
Interphase
During which phase of the cell cycle are the chromosomes duplicated?
Interphase
If you examine a human cell and observe that it has 23 chromosomes, including one Y chromosome, where must it be from?
It must be from a sperm cell (since it is haploid and has a Y chromosome.
The chromosomes line up at the center during which phase of mitosis?
Metaphase
What type of cells undergo mitosis?
Neither bacterial cells or gametes
What would happen if one pair of sister chromatids failed to split during mitosis?
One offspring cell would have one chromosome too many, and the other offspring cell would have one chromosome two few.
The centromeres move away from each other and the nuclear envelope breaks during which phase of mitosis?
Prophase
What are attached at the centromere?
Sister chromatids
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase
Many viruses use RNA, not DNA, as their genetic material. Is the statement, "All life on Earth uses DNA as the genetic material" still accurate?
Yes, viruses are not considered living things
cell theory
all life is cellular and comes from preexisting cells
What are the 3 types of asexual reproduction?
binary fission, plant reproduction, and regeneration
A duplicated chromosome remains tightly paired with its partner at a region called the ______.
centromere
DNA and protein together form a complex called _____.
chromatin
What occurs during prophase?
chromatin condense, nuclear envelope breaks down, nucleolus disappears and spindle fibers begin to form, migration of centrioles
The DNA of every eukaryotic cell is stored in one or more _______ located in the nucleus.
chromosomes
What occurs during metaphase?
chromosomes center at plate, centrioles at the poles, spindle fibers are complete
asexual reproduction
creation of new individual by a lone parent without participation of sperm and egg
Cytokinesis
finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells
Meiosis starts with a single diploid cell and produces __________.
four haploid cells
In sexually reproducing multicellular organisms, the main functions of mitosis are _____.
growth and development and tissue repair/replacement of damaged cell
A pair of chromosomes is known as _____.
homologous chromosomes
cleavage furrow
indentation around the equator of the cell; when the cell separates, it contracts like the pulling of a drawstring which deepens the furrow
A cell preparing to undergo meiosis duplicates its chromosomes during
interphase
chromatin
package of DNA and protein
During meiosis, segments of non-sister chromatids can trade places. This recombination o maternal and paternal genetic information is a key feature of meiosis. During which phase of meiosis does recombination occur?
prophase
The correct order of events during meiosis is
prophase, metaphase, anaphase, telophase, cytokinesis, mitosis 2
Before a cell divides, it copies all of its chromosomes. While the two copies of a chromosome are attached they are called __________.
sister chromatids
What occurs during anaphase?
sister chromatids separate and become sister chromosomes which migrate toward equator, mitotic spindle dissembles
During prophase 1 of meiosis, what do homologous chromosomes do?
stick together in pairs
diploid
two matched set of chromosomes (zygote or somatic cell)
The offspring produced via sexual reproduction are genetically ___ to the parents.
unique
Upon fertilization, the egg and sperm fuse to form a single cell called a ______.
zygote