Cell Division Flashcards
How is DNA organized in a prokaryotic cell?
one, circular chromosome attached to the inside of the cell membrane
How do prokaryotes reproduce?
Binary fission. In this process, a single chromosome makes a copy of itself
How is DNA organized in a eukaryote?
housed in the nucleus and tightly packaged into chromosomes.
What is mitosis used for in eukaryotes?
Mitosis is used to produce new body cells for growth and healing
What are the two main stages of the cell cycle?
interphase, the cell grows and DNA is replicated
mitotic phase, the replicated DNA and cytoplasmic contents are separated and the cell divides.
What happens during the three stages of interphase.
G1 Stage
Cells mature but making more cytoplasm & organelles
Cell carries on its normal metabolic activities
S Stage
DNA is copied or replicated
G2 Stage
All cell structures needed for division are made (eg centrioles)
Both organelles & proteins are synthesized
What are the functions of spindles and centrosomes.
Spindles- necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis
Centrosomes- duplicates and then, move to opposite ends of the cell.
Briefly describe what happens during early prophase of mitosis
The chromosomes become even more condensed, so they are very compact.
The nuclear envelope breaks down, releasing the chromosomes.
Briefly describe what happens during metaphase of mitosis.
At this stage, the two kinetochores of each chromosome should be attached to microtubules from opposite spindle poles.
92 Chromosomes on the Metaphase plate
Briefly describe what happens during anaphase of mitosis.
Chromosomes lined up in the middle will split
Occurs rapidly
Sister chromatids are pulled apart to opposite pole by fibers
Centromere must break for this to happen.
Briefly describe what happens during telophase of mitosis.
Sister chromatids at opposite poles Spindles disassemble Nuclear envelope forms around each set of sister chromatids Nucleolus reappears CYTOKINESIS occurs Chromosomes reappear as chromatin
Differentiate between cytokinesis in plant cells and animal cells.
Plants cell wall forms at the equator to divide cell
In animal cells, cleavage furrow forms to split cell
Briefly describe the types of asexual reproduction.
Binary Fission- The division of a single entity into two or more parts and the regeneration of those parts to separate entities resembling the original.
Mitosis- Reproduction of cells
Meiosis- Process that leads to the creation of gametes
Describe the advantages of sexual & asexual reproduction.
Sexual- Creates more unique offspring
Asexual- Faster and less complex
Differentiate between somatic and germ cells.
Germ Cells= specialized for sexual reproduction
Somatic Cells= do not participate in sexual reproduction; ex. skin cells, muscle cells, etc.
Differentiate autosomes and sex chromosomes
Autosomes=chromosomes with genes that do not determine sex
Sex chromosomes=have genes that determine sex
Differentiate Between diploid and haploid cells.
Diploid=has two sets of chromosomes; somatic cells
Haploid=has one set of chromosomes; gametes
Define zygote
cell formed through fertilization; has a combination of genetic material from both parents
Define fertilization.
when two gametes fuse with each other
Define homologous chromosomes.
chromosomes that are similar in size, shape, and kinds of genes they contain
Compare and contrast mitosis & meiosis.
Mitosis creates two daughter cells while meiosis creates four daughter cells.
Mitosis produces diploid cells while meiosis creates haploid cells.
Mitosis daughter cells are genetically identical while meiosis daughter cells are genetically different.
Describe what happens in Prophase II
Nuclear envelope dissolves
Chromosomes condense
Both have duplicated centromere and migrate to edges of cell
Describe what happens in Metaphase II
the chromosomes line up individually along the metaphase plate
Extra: Nuclear membrane disappears, Microtubules push centrosomes apart and attach chromatids
Describe what happens in Anaphase II
Things pull apart
Sister chromatids split
Describe what happens in Telophase II
Cytokinesis happens
Four daughter cells form
What happens in Prophase I
The chromosomes begin to condense and they also pair up.
Each chromosome carefully aligns with its homologue partner so that the two match up at corresponding positions along their full length.
What happens in Metaphase I
homologue pairs—not individual chromosomes—line up at the metaphase plate for separation.
What happens in Anaphase I
The homologous pairs are pulled apart
What happens in Telophase I
the chromosomes arrive at opposite poles of the cell.
Cytokinesis usually occurs at the same time as telophase I, forming two haploid daughter cells.
Briefly describe what happens in late prophase of mitosis.
The mitotic spindle grows more, and some of the microtubules start to “capture” chromosomes.
What is crossing over and when does it occur?
Crossing over is the swapping of genetic material that occurs in the germ line.
Paired chromosomes from each parent align so that similar DNA sequences from the paired chromosomes cross over one another.
Occurs in Prophase I of Meiosis I.
Compare spermatogenesis with oogenesis.
Spermatogenesis
Two divisions produce 4 spermatids
Spermatids mature into sperm
Produce about 250,000,000 sperm per day
Oogenesis
Produce 3 polar bodies that die and 1 egg
Polar bodies die because of unequal division of cytoplasm
Immature egg called oocyte
Starting at puberty, one oocyte matures in an ovum (egg) every 28 days
List and describe 3 ways that genetic variation is guaranteed during sexual reproduction.
Crossing over (in prophase I) Random assortment of chromosomes (in metaphase I) Random fusion of gametes from different parents.
What is cancer?
Cells reproductive at an uncontrolled rate, take up space
It is a form of uncontrolled meiosis.
What are Oncogenes?
Genes that control cell cycle and cell growth
Can run the risk of cancer
Ex. Braco-1 Gene in for breast cancer
Define Metastasize
Spread to different parts places
How to cure cancer?
Chemotherapy
Attacks all rapidly producing cells or all cells in the body
Radiation has a lot of side effects, i.e. Kills both cancer cells and good cells
Create a virus that only attacks cancer cells.
Viruses have only one RNA
Manipulate virus can only kill cancer cells.
Stop prophase by removing the centriole development or spindle fibers. This stops the start of the germ cell reproduction and allows for cells to no longer reproduce
Remove the part of your body that is more vulnerable to cancer
