Download Introduction to Agriculture, Food, and Natural Resources

Introduction to Agriculture, Food, and Natural
Resources
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Introduction to Agriculture, Food, and Natural
Resources
DNA
Unit 3 – Lesson 3.3 Totally Cellular
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The Nucleus
Eukaryote cells contain a nucleus that
contain important organelle components
and compounds required for cell
replication
Florida State University (2010)
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Inside the Nucleus
Nucleus
DNA
Chromosomes
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Chromosomes
Chromosomes are found within the nucleus
and contain DNA, which is the building
block of genes.
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DNA Defined
Deoxyribonucleic acid – double stranded
nucleic acid molecule arranged as a
double helix.
Main constituent of the
chromosome
Carries the genes as
segments along it’s
strands
Encyclopedia Britannica, Inc.
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DNA Composition
DNA is made up of:
Phosphoric acid
Deoxyribose (sugar)
Four nitrogen bases
– Cytosine (C)
– Thymine (T)
– Adenine (A)
– Guanine (G)
Hydrogen
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DNA Base Pairing
DNA bases always combine as
follows:
• Cytosine (C) combines with Guanine (G)
• Adenine (A) combines with Thymine (T)
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DNA Replication
When cells divide,
DNA strands must
replicate.
Strands unwind
Base pairs detach
Each strand replicates
forming two complete
DNA strands
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Gene Combinations
Genes are “segments” DNA that define
certain physical characteristics of living
things.
Image from ADAM (2009)
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Genetic Inheritance
Genes are replicated as DNA is
copied over and over to make
new cells.
This replication process defines
the physical traits of a living
organism and passes on the
genetic combinations to
offspring during fertilization.
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References
Lab-Aids Incorporated. (2005). The
molecular model of DNA and its replication
kit [Brochure]. Ronkonkoma, NY: Author.
Parker, R. (2010). Plant and soil science:
Fundamentals and applications. Clifton
Park, NY: Delmar.
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