cell division mitosis and meiosis
DESCRIPTION
Cell Division mitosis and meiosis. Limits to Cell Growth. _____ overload (information crisis) Surface area to volume ratio (_____ increases MUCH faster than surface area.) - PowerPoint PPT PresentationTRANSCRIPT
CELL DIVISIONMITOSIS AND
MEIOSIS
_____ overload (information crisis)Surface area to volume ratio (_____ increases
MUCH faster than surface area.)A cell’s s.a. cannot increase fast enough to
meet the demands of the internal volume of the cell. In other words, it will not be able to bring in _____ and get rid of ______ fast enough for the cell to survive.
LIMITS TO CELL GROWTH
_____ within a cell can only diffuse so far no matter how big the cell gets.
For example, if a cell’s volume becomes too great, CO2 will never be able to diffuse out of a cell, thereby killing the cell.
Cells need a large s.a. to take in _____ and excrete _____.
LIMITS TO CELL GROWTH
LIMITS TO CELL GROWTH
Red blood cells have a biconcave surface which increases their surface area making them more efficient at what they do best – exchange gases.
Some review:Not all cells are alike. Even cells within the same organism show enormous diversity in size, shape, and internal organization. Your body contains over _____ different cell types.
Remember, cell _____ fits cell _____!What are stem cells? Let’s see…
The Nature of Stem Cells What are stem cells? (4:10)
CELL DIFFERENTIATION AND STEM CELLS
Binary fission The cell simply copies
its _____ info, separates that info, then splits in half – no distinct _____ occur.
Binary fission (:41) Another one (1:03)
PROKARYOTIC CELL DIVISION
Chromosomes Made of _____ and
_____ Each species has its
own specific number of them. (We have _____ per cell.)
CELL DIVISION
What is a chromosome?
G0 phase – occurs in _____ cells (like brain cells) or in cells that no longer will _____ Most cells stop dividing after about _____ divisions.
G1 phase – cell _____ and produces new _____ and _____. The “no turning back” phase (restriction point)
S phase – chromosomes are _____ and DNA is _____
G2 phase – _____ and molecules needed for _____ are produced
CELL CYCLE – INTERPHASE
Interphase (3:45)
CELL CYCLE – INTERPHASE
Ninety percent or more of the cell cycle is spent in interphase.
Chromatin _____._____ migrate to opposite poles (centrosome)._____ fibers form._____ _____ broken down by enzymes.Nucleus _____.Longest phase of mitosis
CELL CYCLE – PROPHASE
CELL CYCLE – PROPHASE
_____ line up across the equatorial plate._____ _____ attach to kinetochores on
chromatids.
CELL CYCLE – METAPHASE
_____ separated by spindle and pulled to opposite _____ of the cell.
Shortest phase of mitosis
CELL CYCLE – ANAPHASE
New _____ _____ form around chromosomes._____ uncoil and disperse within envelope.New _____ form in each cell.
CELL CYCLE – TELOPHASE
Division of the _____ down the middle of the two new cells.
Plant cells form a _____ _____ which will become the cell _____.
Begins during anaphase once the _____ separate.
CYTOKINESIS
REVIEW OF CELL CYCLE
Another video (1:00)
Mitosis video (1:30)
Some white blood cells, epithelial cells of small intestine – 1 day or less
Red blood cells – 120 daysNeurons, stem cells, kidney cells, eye cells,
some immune cells – lifetimeThe point is, all cells have a _____ which varies
from one cell type to another. What is apoptosis? (_____ _____ _____)About 50-70 billion cells undergo apoptosis dailyApoptosis video (2:55)Another one (1:33)
CELL LIFESPAN
Normally, cells will stop dividing when they _____ each other.
Cells will divide rapidly at sites of _____ (skin cells at a cut for example).
Cyclins – A group of _____ that regulate the _____ _____ (CA, CB,
CD, CE) Different cyclins are _____ at different times in the cell
cycle.Regulators –
A group of proteins that respond to events inside (_____ regulators) and outside (_____ regulators) the cell
REGULATING THE CELL CYCLE
Occurs when cells lose their ability to control their _____. (They don’t respond to _____.)
Many _____ (more than 50%) have a defect in the regulator p53 (p=protein; 53=molecular mass)
p53 was awarded Molecule of the Year in 1998. What an honor!
p53 (1) activates DNA repair proteins; (2) halts the _____ _____ when necessary; (3) initiates _____; and (4) prevents _____ (blood vessel formation)
When the gene that controls p53 is damaged, _____ often form.
CANCER
Differences between benign/malignant/metastatic tumors
What are carcinogens?Cancer explanation (3:50)
What are oncoviruses?
CANCER
Cancer Overview (4:30)
Homologous chromosomes Chromosomes that
contain the same _____ (example: We get one chromo with the eye color gene on it from _____ and one from _____.)
They don’t have identical genes on them; rather, the genes control the same _____.
Meiosis video (2:58)
MEIOSIS
Diploid/Haploid Terms used to describe cells in terms of their
number of _____ Somatic cells – _____ (46) Gametes – _____ (23)
Meiosis is a form of reduction division. It only occurs in the _____ (sperm and egg cells).
There are two distinct divisions – meiosis I and meiosis II
Both divisions are pretty much the same as _____ except prophase I.
MEIOSIS
Prophase I begins with homologous _____ pairing up to form a _____ (four chromatids). Crossing-over occurs during this phase.
Exchange of _____ takes place between homologous chromosomes leading to greater _____ _____.
MEIOSIS
Progression of meiosis in humans: One cell with _____ chromatids in prophase I two
cells with _____ chromatids in prophase II four cells with _____ chromosomes
The final result is four _____ different _____ cells.
MEIOSIS
MEIOSIS
Crossing Over (:43)
Meiosis Video (3:03)
MEIOSIS QUIZ
Division of prokaryotes is called . . .
The four phases of mitosis in order . . .
Volume or surface area grows faster?
# of chromosomes in human somatic cell?
REVIEW TIME!
Two sista ___________ make up a chromosome.
Structures that pull apart chromosomes . . .
The “no turning back phase” . . .
# of chromosomes in human sex cell (gamete)?
REVIEW TIME!
New nuclei form in each daughter cell during . . .
Chromatin condenses during . . .
Chromosomes separated during . . .
REVIEW TIME!
Organelles that produce spindle fibers . . .
Dormant cells are in the _____ phase.
Interphase is subdivided into _______, _______, and _______.
REVIEW TIME!
Chromosomes line up along equatorial plate during?
Nucleus dissolves during . . .
Division of cytoplasm is called . . .
REVIEW TIME!
Describe differences between benign, malignant, and metastatic tumors.
The four main functions of p53 are . . .
Anything that is capable of mutating DNA and causing cancer is a _____.
What is an oncovirus?
REVIEW TIME!
Chromosomes that contain genes that control the same traits are called _____ chromosomes.
What important event occurs during prophase I of meiosis?
Why is this event important?
REVIEW TIME!