Cell Division and Reproduction
cells originate only from?
preexisting cells
What is the term for asexual reproduction where a parent organism, often a single cell, divides into two genetically identical individuals of equal size?
Binary fission
A eukaryotic cell has many (more or less?) genes than a prokaryotic cell and they are grouped into (fewer or multiple?) chromosomes in the nucleus. Each eukaryotic chromosome contains (two or one?) long DNA molecule…
-more
-multiple
-one
Describe a chromosome versus a chromatid
Chromosome: a strand of DNA, a functional unit of inheritance, consists of a single, double-stranded DNA molecule
Chromatids: are half of a replicated chromosome.
Before cell division, chromosomes are copied, and identical chromosome copies join together at their centromeres. Each strand of one of these chromosomes is a chromatid. Joined chromatids are known as sister chromatids.
How many daughter cells does Mitosis produce?
two identical daughter cells
(asexual or sexual reproduction?) creates a variety of offspring.
sexual reproduction
Prokaryotic cells reproduce asexually by ? , a term that means “dividing in half.”
binary fission
What is chromatin?
The complex of DNA and protein is called chromatin. The proteins involved in packaging the DNA
The two sister chromatids are attached together at a region called the ?
centromere
most of the cell cycle is spent in what phase?
interphase
What is asexual reproduction?
producing offspring that are all genetic copies of the parent and identical to each other (clones).
In typical prokaryotes, most genes are carried on one (ladder, or circle-shaped?) DNA molecule that, with associated proteins, constitutes the organism’s single chromosome
circular
You view an animal cell through a microscope and observe dense, duplicated chromosomes scattered throughout the cell. Which state of mitosis are you witnessing?
Prophase (because the chromosomes are condensed but not yet aligned)
When does a chromosome consist of two identical chromatids?
When the cell is preparing to divide and has duplicated its chromosomes but before the duplicates actually separate
-Prophase
Put the different parts of interphase in order
S
G2
G1
G1- first gap
S- DNA synthesis
G2- second gap
? accounts for about 10% of the total time required for the cell cycle
The mitotic phase
-mitosis
Why is binary fission classified as asexual reproduction?
binary fission creates an exact clone of the parent organism which falls under asexual reproduction
-no genetic variation
The ? of a eukaryotic cell are duplicated before they condense and the cell divides.
chromosomes
In the first stage of cell division, during which the chromatin (expands or condenses ?) to form ?
-condenses
-sister chromatid
Typically, ? lasts for at least 90% of the total time required for the cell cycle.
interphase
What function does cell division play in an amoeba (a single-celled protist)? What functions does it play in your body?
Reproduction; development, growth, and repair
Label in order:
parent cell divides into two daughter cells
the copies move apart
the plasma membrane pinches inward
the cell replicates its single chromosome
more cell wall is made
1. the cell replicates its single chromosome
2. the copies move apart
3. the plasma membrane pinches inward
4. more cell wall is made
5. parent cell divides into two daughter cells.
Before a cell starts dividing, the chromosomes duplicate, producing ? (containing identical DNA) that are joined together along their lengths.
Sister chromatids
When are the chromosomes visible under a microscope? and why?
Chromosomes become visible during prophase.
The chromatin fibers begin to condense during the prophase stage and are visible until the end of cell division.
A researcher treats cells with a chemical that prevents DNA synthesis from starting. This treatment would trap the cells in which part of the cell cycle?
G1