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DNA Structure and Function
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DNA-Introduction
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DNA- DeoxyriboNucleic Acid
Located in most all cells Specifically in the nucleus Makes up chromosomes Controls all cell activities
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DNA-Discovery James Watson American Biologist and Francis Crick English Physicist – put together the structure of DNA - model
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DNA-Discovery
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DNA-Strucure Shape is that of a Double Helix- “twisted ladder”
Made up of: -Deoxyribose Sugar -Phosphate molecule -Nitrogen Bases
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DNA Structure The basic unit or building block is called a Nucleotide
It is made up of: - Deoxyribose Sugar - Phosphate Group - Nitrogen Base
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DNA-Structure Sides of the ladder are made up of alternating molecules of: -Phosphate -Deoxyribose Sugar
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DNA-Structure The middle or “rungs of the ladder” are made up of Nitrogen Bases There are FOUR different types of Nitrogen Bases They are joined by weak Hydrogen Bonds.
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DNA-Structure Base Pair Rule: Adenine (A) bonds with Thymine (T)
Cytosine (C) bonds with Guanine (G)
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DNA Candy Model
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DNA-Structure DNA “winds up” and condenses to make Chromosomes.
Genes are segments of DNA located on specific sites on chromosomes that code for a specific Protein.
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DNA Replication Process in which DNA makes an exact copy of itself
Takes place in the Nucleus Provides a set of instructions for new cells –growth or healing
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DNA-Replication STEPS:
DNA unzips – hydrogen bonds between nitrogen bases are broken by an enzyme. Free nucleotides in nucleus line up with exposed nitrogen bases – helped by another enzyme Bonds are formed between sides and nitrogen bases leaving 2 DNA molecules each made up of one original strand and one newly formed strand. VIDEO:
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DNA- Replication
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Chromosomes Chromosomes are identified by their size, location of centromere and banding pattern.
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Parts of a Chromosome Telomere – the end or tip of a chromosome
Centromere – part of where spindle fibers attach Chromatid – one copy of a newly copied chromosome which is still joined to the original chromosome by a single centromere
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Homologous Chromosomes
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Human Chromosomes
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Mitosis – Cell Division
Why would a cell need to divide? What process would need to take place BEFORE cell division occurs? What type of cells undergo Mitotic Division? What does Mitosis mean?
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Mitosis – Cell Division
ANSWERS: Make more cells for growth or repair. Replication Body Cells or SOMA Cells – Asexual Reproduction “Mito” = thread-like “osis” = condition Let’s Take a Look!!
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Mitosis Is a process where a single cell divides into two daughter cells division of the nuclear material occurs in eukaryotic cells: animal & plant Daughter cells are exact copies of the parent cells in number and kinds of chromosomes 2n--) 2n Video : Brain Pop
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Mitosis – Plant Cells
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Mitosis – Stages of
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Inter - Between
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Pro - First
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Meta - MIddle
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Ana - ???
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Telo – End
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Mitosis – Animal Cells
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Mitosis Plant Cell
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Mitosis Animal vs Plant
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Quiz - Mitosis
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