This document discusses mitosis and defines it as the process where a cell duplicates its genetic material and divides into two identical daughter cells. It describes the important cell structures involved like chromatids, centromeres, and centrioles. The stages of mitosis - interphase, prophase, metaphase, anaphase, telophase, and cytokinesis - are explained in detail. Cytokinesis, the final stage where the cytoplasm splits into the two daughter cells, differs between animal and plant cells.
Reproduction means producing offspring that may or may not be exact copies of their parents. It is a part of a life cycle, which is a series of events wherein individuals grow, develop, and reproduce according to a program of instructions encoded in DNA, which they inherit from their parents. When cells divide, each daughter cell receives a complete copy of DNA and enough cytoplasmic machinery to start up its own operation. DNA contains the blueprints for making different proteins.
Reproduction means producing offspring that may or may not be exact copies of their parents. It is a part of a life cycle, which is a series of events wherein individuals grow, develop, and reproduce according to a program of instructions encoded in DNA, which they inherit from their parents. When cells divide, each daughter cell receives a complete copy of DNA and enough cytoplasmic machinery to start up its own operation. DNA contains the blueprints for making different proteins.
Reproduction means producing offspring that may or may not be exact copies of their parents. It is a part of a life cycle, which is a series of events wherein individuals grow, develop, and reproduce according to a program of instructions encoded in DNA, which they inherit from their parents. When cells divide, each daughter cell receives a complete copy of DNA and enough cytoplasmic machinery to start up its own operation. DNA contains the blueprints for making different proteins.
Reproduction means producing offspring that may or may not be exact copies of their parents. It is a part of a life cycle, which is a series of events wherein individuals grow, develop, and reproduce according to a program of instructions encoded in DNA, which they inherit from their parents. When cells divide, each daughter cell receives a complete copy of DNA and enough cytoplasmic machinery to start up its own operation. DNA contains the blueprints for making different proteins.
The study of the cell cycle focuses on mechanisms that regulate the timing and frequency of DNA duplication and cell division. As a biological concept, the cell cycle is defined as the period between successive divisions of a cell. During this period, the contents of the cell must be accurately replicated.
The cell cycle is regulated by cyclins and cyclin-dependent kinases.
How long is one cell cycle?
Depends. Eg. Skin cells every 24 hours. Some bacteria every 2 hours. Some cells every 3 months. Cancer cells very short. Nerve cells never.
Programmed cell death:
Each cell type will only do so many cell cycles then die. (Apoptosis)
I really need help drawing each stage of mitosis for the oni.pdfabhiehomeapp2002
I really need help drawing each stage of mitosis for the onion root tip in this. I also need help label
each drawing with these terms: terms: nucleus, nucleolus, chromatin, chromosomes, metaphase
plate, daughter chromosomes, and cell plate. (Not all of these structures will be found in all
stages).
Late prophase Metaphase Anaphase Telophase and cytokinesisLaboratory 14: Mitosis and Cell
Division in onion root tips Cells are the basis for life, and they must reproduce for life to continue.
Cells reproduce by a process called cellular reproduction, or cell division. Cell division occurs in all
living organisms as they grow, repair, and reproduce. Bacteria, the simplest living things,
reproduce by a process called binary fission. In binary fission, the bacterium's single chromosome
is duplicated (replicated), the two chromosomes are separated, and then the plasma membrane
and cell wall grow inward, dividing the cell in two. Higher organisms like animals, plants, and fungi,
have many chromosomes, and have a more complex form of cell division. The chromosomes must
first be replicated (copied) and then they must be divided up into two perfectly identical sets or
groups. Only after production of two identical sets of genetic information can the cell successfully
divide. The formation of two identical sets of genetic information (two separate nuclei) is called
mitosis. The division of the cytoplasm is called cytokinesis. Cell division occurs once during the
"lifetime" of a cell, or what is called the cell cycle. The cell cycle has two phases, which are called
interphase and the mitotic phase. Interphase is a period where little cellular activity can be seen,
and most of a cell's lifetime is spent in this phase. However, in a cell that is preparing to divide,
interphase becomes a time in which the cell's DNA molecules (its chromosomes) are replicated,
the cell increases its supply of proteins, and the number of cellular organelles is increased. The
mitotic phase has two events: mitosis and cytokinesis. Mitosis is the process in which the cell
nucleus and its contents (most importantly the chromosomes) are divided and evenly packaged
into two identical daughter nuclei. During cytokinesis, the cell's cytoplasm is divided in two. When
the mitotic phase ends, there are two identical cells present where only one existed before (pages
179-182, A Guide to the Natural World).The Cell Cycle The term cell cycle is used to describe the
life history of living cells. It consists of interphase and the mitotic phase. Interphase cells that are
going to divide increase their cell contents and replicate their chromosomes. Mitotic cells have
completed interphase and are in the process of forming identical daughter nuclei (mitosis) and
dividing the cell's cytoplasm into two separate cells (cytokinesis). Interphase The cell cycle is
divided into phases, even though it is really a continuous process. Interphase has three phases:
G1, S, and G2. During interphase, DNA, with .
3. Mitosis defined
Mitosis is the process, in the cell cycle, by which a
cell duplicates into two genetically alike
(identical) daughter cells.
4. Important Cell Structures
Involved in Mitosis
Chromatid – each strand of a duplicated
chromosome
Centromere – the area where each pair of chromatids
is joined
Centrioles – tiny structures located in the cytoplasm of
animal cells that help organize the spindle
Spindle – a fanlike microtubule structure that helps
separate the chromatids
7. Interphase
The cell builds up energy
It grows and copies its chromosomes in preparation for
cell division.
8. Prophase
During prophase the duplicated
chromosome condenses and
becomes visible.
The centrioles move to
opposite sides of nucleus and
help organize the spindle.
The spindle forms and DNA
strands attach at a point called
their centromere.
The nucleolus disappears and
nuclear envelope breaks down.
9. Metaphase
the centromeres of the duplicated
chromosomes line up across the
center of the cell.
The spindle fibers connect the
centromere of each chromosome
to the two poles of the spindle.
10. Anaphase
the centromeres are pulled apart
and the chromatids separate to
become individual chromosomes.
The chromosomes separate into
two groups near the poles of the
spindle.
11. Telophase
the chromosomes spread out
into a tangle of chromatin.
A nuclear envelope re-forms
around each cluster of
chromosomes.
The spindle breaks apart, and
a nucleolus becomes visible in
each daughter nucleus.
12. Cytokinesis
How do daughter cells split apart after mitosis?
Cytokinesis completes the process of cell division – it splits one cell into
two.
13. Cytokinesis is the division of the cytoplasm.
The process of cytokinesis is different in animal and plant cells.
Cytokinesis
14. Cytokinesis in Animal
Cells The cell membrane is drawn in until the cytoplasm is pinched into
two equal parts.
Each part contains its own nucleus and organelles.
15. Cytokinesis in Plant Cells
In plants, the cell membrane is not flexible enough to
draw inward because of the rigid cell wall.
Instead, a cell plate forms between the divided nuclei
that develops into cell membranes.
A cell wall then forms in between the two new
membranes.