Cell Division When do cells divide? How do cells divide? What is Meiosis? How do Chromosomes combine...
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Transcript of Cell Division When do cells divide? How do cells divide? What is Meiosis? How do Chromosomes combine...
Cell Division
•When do cells divide?•How do cells divide?•What is Meiosis?•How do Chromosomes combine and form new chromosomes?
Cell Size
• All living organism have same size cells
• The size of the animal does not affect the size of the cell
• Mouse cell size = elephant cell size
Eukaryotic Cell Size
• Cell membrane determines cell size• Why? Allows nutrients to enter or
exit• Larger cells require a larger cell
membrane
Volume
• The amount of space occupied by a three-dimensional object or region of space, expressed in cubic units.
Ratio
• Ratio • The comparison between 2 numbers
How do you write a ratio of 4 to 8?• 4:8• 4/8• Surface Area : Volume
Bigger is Not Better
• Cells need to remain small to survive• Larger cells have a small SA : V ratio• Makes it difficult to transport
materials into or out of the cell
• Nucleus controls the cells size
Cell Division
• Cells divide when they reach their maximum size
• Cell division = one cell split and becomes
2 cells
Growth
• Cells divide to increase the size of the organism
• Differentiation: cells develop specialized shapes and functions
• Ex. Nerve cells, heart cells, intestine cells, intestine cell
• Each cell has a unique function
Repair
• Repairs tissue• Mending of skin, blood vessels, and
bone• Regeneration of old skin cells
• Regeneration: ability to replace a missing body part, like a starfish or worm
Reproduction• Asexual reproduction: one parent
produces an offspring• Offspring is genetically IDENTICAL
to parent
• Sexual Reproduction: 2 parents produce an offspring
• Offspring has a combination of genetic material
Sexual Reproduction
• Gamete = reproductive cell; sperm or egg
• Two gametes fuse to form a zygote
Gametes
zygote
Zygote
• Divides millions x • Becomes an individual• Humans, some plants, animals
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