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  1. What is an allele?
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    • Alleles are different forms of the same gene.  Different alleles produce variations in inherited characteristics such as eye color or blood type.
  2. What is a chromosome?

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    • A chromosome is a structure found in the nucleus of a cell which contains genes.  Chromosomes come in pairs, and a normal human cell contains 46 chromosomes (22 pairs and two sex chromosomes.)
  3. What is DNA?

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    • DNA is the substance of heredity; it carries genetic information.  DNA stands for deoxyribonucleic acid.
  4. What is a genotype?
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    • A genotype is the actual allele or gene carried by an individual.
  5. What is heredity?
    Heridity is the process by which traits are passed from parent to offspring (children).
  6. What does heterozygous mean?

    is having two different alleles for a given gene.  Heterozygous is another term for hybrid.
  7. What is a double helix?
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    • A double helix is the shape of DNA.
  8. What is base paring?
    Base paring is the chemical rule that governs how DNA is assembled where adenine bonds with thymine (A to T) and guanine bondswith cytosine (G to C).

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  9. What are Genes?
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    • Genes are a unit of heredity information, made up of DNA, and found on the chromosome.
  10. What is genetic code?
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    • Genetic order is the exact order of nucleotides in a gene.
  11. What does homozygous mean?
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    • Homozygous is having identical alleles for a given gene.
  12. What is a nucleotide?
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    • A nucleotide is the base (holds genetic material) and spine of DNA. 
    • It has three parts:
    • 1) chemical base
    • 2) phosphate
    • 3) sugar molecule
  13. Define traits of an organism.
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    • Traits of an organism include blue eyes, blonde hair, big ears, small nose, height... (its phenotype)
  14. What is a mutation?
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    • A mutation is a change in DNA caused by a mutagen (an agent such as a chemical, ultraviolet light, or radioactive element)... or when DNA copies itself.
  15. What is genetics?
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    • Genetics is the study of heredity and the variation of inherited characteristics.
  16. Where are chromosomes found?
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    • Chromosomes are found inside the nucleus.
  17. Who is known as the "Father of Genetics?"
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    • Gregor Mendel is known as the Father of Genetics.
  18. What is a dominant gene?
    • A dominant gene is an allele that is expressed when it is with another allele. The second allele could be dominant or recessive.  Ex:  Tt, TT, Rr, RR
    •  (Dominant genes are written in capital letters.)
  19. What is a Punnet Square?
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    • A Punnet Square is a mathemtical tool used to predict the likelihood of an offspring inheriting different traits.
  20. What is a phenotype?
    • A phenotype is an observable trait of an organism... 
    • haircolor
    • weight
    • diseases; Huntington's disease
  21. What would a homozygous recessive genotype look like?
    A homozygous recessive genotype would look like...


    Homozygous resssive means possessng two copies of the same allele, both recessive.
  22. How many chromosomes does a human body cell have?
    There are 46 chromosomes in a human body cell.  All of these are in the form of pairs.  There are 23 pairs of chromosomes in a human body cell.
  23. What would a hybrid genotype look like?
    A hybrid genotype would look like...

    Mm,  Ff,  Gg,   Ll,   Ss,   etc.
  24. What is a nucleotide made up of?
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    • Nucleotides are made up of three parts.
    •   A five carbon sugar
    •   A nitrogen base
    •   A phosphate group
  25. What are the 4 chemicals that create all genetic sequences in DNA:
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    • The four chemicals that create all genetic sequences in DNA are...
    • Adenine
    • Guanine
    • Cytosine
    • Thymine
  26. What does DNA stand for?
    • DNA stands for....
    • Deoxy  ribo  nucleic  Acid
  27. What is the Human Genome?
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    • The human genome is the full collection of genes needed to produce a human being.
  28. Who discovered the shape (double helix) of DNA?
    The shape of DNA was discovered by James Watson, an American molecular biologist and Francis Crick, a British molecular biologist.
  29. What is DNA replication?
    DNA replication is when DNA makes a copy of itself.  It splits in half and forms two strands.
  30. Look at the DNA strand.  Identify the four bases and the sugar phosphate backbone.
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  31. The four states of mitosis are...
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    • 1) Prophase - Nucleus breaks down and chromosomes form 
    • 2) Metaphase - Chromosomes line up in the center
    • 3) Anaphase -Chromosomes moving to the opposite poles
    • 4) Telophase - Cytoplasm divides and the spindle fiber begin to disappear (Cytokinesis)
Card Set:
2013-01-21 18:09:36
6th Grade Science DNA Test Review

alleles, chromosomes, DNA, genotype, heredity, heterozygous, double helix, base paring, genes, genetic code, nucleotide, traits, mutations, homozygous, punnet square, phenotype, father of genetics, hybrid
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