Unit 4 Inheritance of Traits Part 1 Cells and DNA

Prokaryotic Cell A Bacterial cell that has simple structures and a circular piece of DNA

Eukaryotic Cell Any cell other than a bacterial cell (plants and animals) that have complex membrane bound structures and multiple strands of DNA enclosed within a nucleus.

DNA Deoxiribonucleic Acid , DNA, is a double helix shaped (twisted ladder) of chemical monomers (small parts) called nucleotides

Where is DNA found? DNA is found in the nucleus of Eukaryotic cells and in the cytoplasm of Prokaryotic cells.

Chromatin DNA strands coiled loosely around histone proteins.

Chromosome Before cell division, the Chromatin coils into very dense chromosomes. The number of chromosomes varies depending on the species.

Why is DNA important? It’s chemical structure stores the information necessary for making proteins the organism needs for survival.

Nucleotides: Chemical monomer that makes up DNA 3 nucleotide parts Deoxyribose sugar Phosphate Nitrogen base - adenine (A) - thymine (T) - guanine (G) - cytosine (C)

Nucleotides always pair in the same way. base-pairing rules A pairs with T G pairs with C C G T A

Anti-parallel The two The two DNA strands are antiparallel to each other, they run in opposite directions. https://www.youtube.com/watch?v=qy8dk5iS1f0

A T G G A C T A C T A C C T G A T G Practice If one side of DNA has this base sequence, what does the other side have? A T G G A C T A C T A C C T G A T G

DNA Base Sequence The sequence of the bases on the DNA strand code for certain proteins to be made. These areas are called GENES. Not all parts of DNA code for proteins.

Genes Genes are regions of DNA within the chromosome that code for proteins that determine traits.

DNA Replication Within the nucleus there are molecules (enzymes) that copy the DNA before cell division. This way the new cell has an exact copy of DNA from the first.

Cell Division = Mitosis

Results of Mitosis DNA doubles Original DNA and Copy DNA “sister chromatids” separate into different cells Produces 2 “daughter cells” from 1 cell Exactly the same DNA in each cell.