Intro To Cell Division Flashcards
When does cell division occur in humans and other organisms?
Different times in their life.
What is the purpose of cell division in unicellular organisms?
It may be used as a form of asexual reproduction.
What is the purpose of cell division in multicellular organisms?
May be used in growth, repair, and development, and a different kind of cell division forms gametes.
What are gametes?
Reproductive cells used in sexual reproduction.
What are the two forms of cell division called?
Mitosis and Meiosis
In humans, which form of cell division is more common?
Mitosis.
The process of mitosis is used when?
During asexual reproduction and growth.
What is mitosis?
The process by which the nucleus of a cell divides to two new nuclei. Each nucleus that is created contains an identical copy of DNA.
What is meiosis?
Lthe process by which gametes are created.
What are the male gametes called?
Sperm cells.
What are the female gametes called?
Egg cells, or ova.
Why must the process of meiosis must form cells that have half the amount of DNA as body cells?
Because the egg and sperm will join each other during sexual reproduction.
What are genes?
Segments of DNA that codes for a specific trait.
What is DNA organized into?
Genes.
What does a single DNA molecule have?
Thousands of genes lined up, one after another.
Where is the DNA when a cell is not in the process of dividing?
Spread apart within the nucleus, appears grainy.
What is chromatin?
The name for the phase of the DNA when it is spread apart in the nucleus and appears grainy.
What does the DNA do when a cell is dividing?
Coils up with certain proteins to form a structure called a chromosome.
Why is a chromosome made up of exact copies? What are these copies called?
Before the DNA coils up, it is copied. Chromatids.
Where do the chromatids attach? What is this area called?
Near the middle at an area called the centromere.
How many chromosomes does a fruit fly have?
8.
How many chromosomes does a human have?
46.
How many chromosomes does a dog have?
78.
What does asexual reproduction require?
Only one parent.
What kind of organism reproduces asexually?
Unicellular organisms.
What does sexual reproduction require?
Two different parent cells from two separate organisms.
What does sexual reproduction produce?
Offspring that are genetically different from each parent.
How much DNA does sexually reproduces offspring receive from each parent?
50%. Impossible to get more from one parent than the other.
Where are gametes produced?
The gonads.
What are the gonads?
The sex organs.
What is fertilization?
The joining of the nucleus of the male gamete with the nucleus of the female gamete.
What does fertilization form?
A single cell called a zygote.
What happens to the chromosomes when a sperm cell fertilizes an egg cell?
The chromosomes of both parents are combined.
Excepting the sex cells, each human cell has how many chromosomes and why?
46, because two copes of 23 chromosomes.
Regarding the x and y chromosomes, which one forms a male? Which one forms a female?
XY is male and XX is female.
What are homologous chromosomes?
Chromosomes that have the same gene.
Where are homologous chromosomes found?
Each of the twenty three pairs of chromosomes in a human consist of two homologous chromosomes.
What can be different about two homologous chromosomes?
There may be a different version of the same gene.
Where does each homologous chromosome of a pair come from?
One from each of the two parents.
What are body cells that AREN’T gametes called?
Somatic cells.
Why are somatic cells called diploid?
Because they have two of each type of chromosome.
Why are gametes called haploid?
Becaause they only have one of each type of chromosome.
What term to biologists use to represent haploid and diploid?
N for haploid, 2N for diploid.
According to the terms for haploid and diploid, what is the status for humans?
N=23,2N=46
How are gametes formed?
Meiosis.
What is meiosis?
A type of cell division that results in cells with half the number of chromosomes as the parent cell. Used to form gametes.
How many rounds of division does meiosis involve?
2.
What is a different name for cell division?
Cell reproduction
