Transcript Cell Growth and Division

Cell Growth and Division
Ch. 10
10.1
Cell Reproduction
• How/why does the body grow in size (multicellular organisms)?
***ANSWER THIS QUESTION!!
• cells obtain nutrients and eliminate wastes through
the______________.
• cells need to remain relatively _____ to survive.
• 2 factors that limit/determine cell size:
1. surface area
2. volume
(sa:v)
**cells w/ a greater sa:v are able to work more efficiently
Why do cells divide?
• 3 reasons:
– Growth
– Repair
– Reproduction
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Remember the Cell Theory?
(Bio A)
• Cells are the basic units of structure and
function in organisms.
• All living things are made up of one or
more cells.
• All cells arise from existing cells.
Preparing to Divide:
• Copy DNA…why? ***ANSWER THIS QUESTION!!
• Prokaryotic cells:
– Have a singular circular molecule of DNA
• Analogy: Rubber band
– Cell doubles in size  DNA copied  cw pinches in  2 genetically
identical daughter cells
• Analogy: Balloon animal
• Eukaryotic cells:
– DNA is packaged into highly condensed chromosome structures with
the help of proteins
– DNA + proteins = chromatin
– Challenging b/c all of the cell’s DNA must fit inside of the nucleus
– Much more complex process than in prokaryotic cells
Confusing! Is it a chromosome,
chromatin, or chromatid?
• Chromosome: a cellular structure that carries genetic
information
– genes are located on chromosomes.
– may have many forms
• Chromatin: the substance that makes up chromosomes
(DNA wrapped around proteins called histones)
– Looks like “beads on a string”
• When DNA is copied (preparing for cell division), each
copy is called a chromatid.
– when joined together by a centromere, the 2 chromatids together
(called sister chromatids) are considered one
chromosome…when separated (during cell division), each
chromatid is considered its own chromosome.
• Draw it!! (w/ labels)…on white board 