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Flashcards in Biology - Cell Cycle Deck (28):

What is another name for body cell and how many chromosomes?

Somatic/Vegetative cells
46 chromosomes


What is another name for sex cell and how many chromosomes?

Gametes/Germline cells
23 chromosomes


What happens in interphase?

- cell grows and carries out regular cellular functions
- cell duplicates DNA to prepare for mitosis (each of the 46 DNA molecules now consist of 2 identical sister chromatids)


What happens in mitosis?

- division of DNA
- must occur before cell divides
- ensures that complete set of DNA is given to each daughter cell


What is visible in interphase?

nucleus + nucleolus + nuclear membrane


Mitosis allows what?

- single cells to reproduce
- multicellular organisms to grow and develop
- tissues to be repaired
- old worn out cells to be replaced


Each body cell has __ DNA molecules; __ from maternal set and __ from paternal set

46 DNA molecules (23 from maternal, 23 from paternal)


During interphase, DNA molecules gets copied to now each of __ molecules contain ___________.

46 DNA molecules get doubled; each 46 DNA molecules contain 2 identical sister chromatids


Alone, a strand of the sister chromatids would be called _______. The sister chromatids are held together by __________.

Sister chromatids are held together by a centromere


What is cytokinesis and the end result?

- the division of cytoplasm + organelles
- end result is 2 genetically identical daughter cells


What happens in animal cytokinesis?

a band of protein squeezes cell membrane in middle, forming cleavage furrow until cytoplasm splits


What happens in plant cytokinesis?

cell plate grows in the middle outward, sealing contents of new cells from each other


What happens in prophase?

- chromatin condense to chromosomes made up of 2 sister chromatids
- nuclear membrane starts to dissolve, releasing chromosomes into cytoplasm
- centrioles move to opposites poles with spindle fibers


What is visible in prophase?

maybe nucleus + nucleolus + nuclear membrane, chromatids, chromosomes, and spindle fibers


What happens in metaphase?

- chromosomes line up along equatorial plate
- nuclear membrane dissolves completely


What is visible in metaphase?

chromatids, chromosomes, spindle fibers


What happens in anaphase?

- sister chromatids separate into daughter chromosomes, pulled to other end of cell by spindle fibers (which contract opposite ways)


What is visible in anaphase?

chromosomes, spindle fibers


What happens in telophase?

- chromosomes reach opposite ends of cell and lengthen to chromatin
- new nuclear membrane + nucleus + nucleolus form at each end of cell
- spindle fibers break down and disappear


What is visible in telophase?

nucleus + nucleolus + nuclear membrane, maybe chromosomes


What are spindle fibers?

a network of protein which grows from centrioles and attach to the centromere of each DNA molecule


What is the equatorial plate?

located in middle of cell, equal distance away from 2 poles and perpendicular to spindle fibers


Sexual reproduction?

The process of producing offspring by the fusion of 2 gametes; the production of offspring that have genetic information from each parent


Asexual reproduction?

The process of producing offspring from only one parent; the production of offspring that are genetically identical to the parent


What do all organisms need to survive?

cell division + source of energy + nutrients + water + gases to survive


As multicellular organisms, why do number of cells increase instead of size?

Chemicals used during cell activity/growth enter across the membrane and travel through diffusion; where chemicals move from an area of higher concentration (amount of solute in a solution) to lower. Water enters and leaves in a process called osmosis whereas water moves in the direction of greater solute concentration. But when a cell gets too large, these necessary chemicals/water cannot move through the cell fast enough and will die!


How does a minor cut heal over time?

Every day, your body sheds millions of dead skin cells, all of which are replaced by new ones. If you get a cut, cells divide to fill in the gaps.



A cell should remain in interphase and not divide if:
1. signals from surrounding cells tell it not to divide
2. there are not enough nutrients to provide for cell growth
3. DNA within nucleus has not been replicated
4. DNA is damaged