Module 4 Flashcards
2 reasons why cells divide
Grew too large (increase SA:V ratio)
Replace a dead cell
Why does DNA stop working well as the cell grows?
DNA doesn’t increase in size
Does the surface area and volume of a cell equal each other or no?
They do not equal the same amount
What is cell division? How is it beneficial?
A cell divides into 2 daughter cells; identical to the original. It decreases the size, reducing the strain and cell volume
As the cell enlarges, what happens to the SA to Volume ratio?
Decreases
Ex: 6:1 … 2:1
What are the types of reproduction?
Asexual and sexual
What are the benefits and drawbacks of asexual reproduction?
Doesn’t need two organisms ~ easier with a lower population
Genes do not change, no adaption
What are the benefits and drawbacks of sexual reproduction?
Different genes ~ can adapt
Needs 2 parents; difficult with low population
What are the differences in DNA between eukaryotes and prokaryotes?
Eukaryotes: DNA in the nucleus, more DNA, chromosomes
Prokaryotes: DNA in cytoplasm
What are the 4 phases of cell division AND what happens during the phase
G1: Growth
S: DNA Synthesis (2x DNA as beginning)
G2: Growth+Prep for Mitosis (shortest, organelles and molecules are produced)
M: Mitosis (2 daughter cells; mitosis and cytosis stages)
What is/happens during the second stage of mitosis?
Metaphase: centromeres of chromosomes line up through cell center, spindle fibers connect to centromeres
What is/happens during the third stage of mitosis?
Anaphase: chromatids separate into 2 separate groups
What is/happens during the first stage of mitosis?
Prophase: genetic materials shrink, spindle forms in centrosome, centrioles move to opposite ends of cell
What is/happens during the fourth stage of mitosis?
Telophase: chromosomes spread into chromatin, nuclear envelope reforms, nucleus forms in daughter cells
What happens during cytokinesis in animal cells?
Cell membrane pinches inward, forming cleavage furrow
What happens during cytokinesis in plant cells?
Cell plate forms between nuclei, forms cell wall later
What is asexual cell division called?
Binary fission
What happens during binary fission?
DNA is replicated,cytoplasmic membrane elongates to separate DNA, cross wall forms + membrane leaves, cross wall fully separates new daughter cells
What is the difference between centrosomes, centrioles, and centromeres?
Centrosomes: end of cell where spindle fibers come from
Centrioles: pieces in center of centrosome
Centromeres: center of chromosomes
What is the difference between chromosomes and chromatids?
Chromosomes are made of two chromatids
What is cyclin?
A regulatory protein that regulates the cell cycle
What are the types of regulatory proteins, what do they do?
Internal: makes cell cycle wait for the previous step to finish correctly
External: signals to speed or slow the cycle
What are growth factors?
They help the growth/division rates, but slows other cells’ cycles (filling chair example)
What is apoptosis?
Programmed cell death; important for development
What happens during apoptosis?
cell + chromatin shrink
membrane breaks off
neighbor cells clean excess
What does cancer do?
Takes nutrients from healthy tissues
Causes of cancer
Genetics, infections, smoking/tobacco, radiation; all with no control of cell cycle
Treatments for cancer
Localized: surgery
General: radiation (chemotherapy)
What does chemotherapy do?
Kills the cancer cells, but also harms healthy cells in the process
What is the alternate stage of mitosis?
Go: rest stage, can’t get out of, no division
What is an internal regulator? (Throughout the mitosis cycle)
Checkpoints (ex. DNA copied correctly, spindle fibers attached to chromatids)
What are the types of tumors?
Benign and malignant
What are the characteristics of benign tumors?
Not cancerous, slower spreading, noninvasive
What are the characteristics of malignant tumors?
Cancerous, spread quickly
Metastasis?
Spread of tumor cells throughout whole body
