Chromosomes DNA Replication DNA Chromosomes Prokaryotes circular chromosomes

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Chromosomes & DNA Replication

Chromosomes & DNA Replication

DNA & Chromosomes Prokaryotes Øcircular chromosomes ØDNA is found in cytoplasm Eukaryotes ØLocated in

DNA & Chromosomes Prokaryotes Øcircular chromosomes ØDNA is found in cytoplasm Eukaryotes ØLocated in nucleus Ø 1000 x more DNA than prokaryotes ØNumber of chromosomes varies (human has 46, fruit flies has 8)

DNA Length Very long DNA in one human cell is one meter long Ex:

DNA Length Very long DNA in one human cell is one meter long Ex: Imagine stuffing 300 m of rope into your back pack

Chromosome Structure Contain DNA & protein (histones) packed together called chromatin Not visible until

Chromosome Structure Contain DNA & protein (histones) packed together called chromatin Not visible until cell division

Chromosome Structure

Chromosome Structure

DNA Replication Before a cell divides it copies its DNA (replication) Each new cell

DNA Replication Before a cell divides it copies its DNA (replication) Each new cell now has a complete set of DNA The DNA molecule separates into two strands Two new strands follow the rules of base pairing (C with G, A with T) EX: a sequence of base pairs with TACGTT would have a complimentary strand of ATGCAA

DNA Replication

DNA Replication

Cell Reproduction Facts Adults produce about 2 trillion cells a day Replacement cells are

Cell Reproduction Facts Adults produce about 2 trillion cells a day Replacement cells are exact copies of the old cells Some cells, like hair & nails, are replaced constantly Other cells, like brain & nerve cells are rarely replaced Replicating DNA provides both daughter cells with a complete set of DNA.

Cells divide because Large cells an inefficient. (diffusion of wastes/nutrients take too long) Growth

Cells divide because Large cells an inefficient. (diffusion of wastes/nutrients take too long) Growth & Development Replace old cells Replace damaged cells