Transcript Understanding Living Things - Lockwood School in Billings, MT

Understanding Living Things
Cells, Genetics, and Heredity
Harcourt Science
Chapter 1
Mrs. Strand
6th grade
Lockwood Middle School
Cells, Genetics and Heredity
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Terms
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Cell membrane
Cell wall
Cytoplasm
Mitochondria
Chloroplast
Vacuole
Nucleus
Chromosome
Nuclear Membrane
How Plants & Animal Cells Differ
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The discovery of cells
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Robert Hooke
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One of the first people to see and study the
tiny building blocks that made up living things
Gave cells their name, because they looked
like small prison cells
Cell Theory
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Cells are the basic building blocks of
all living things
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All live activities take place in cells
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Large organisms have more cells that
can do different things
Heart, lungs, kidneys, skin…
New cells are only produced by
existing cells
How Plants & Animals Differ
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http://www.beyondbooks.com/lif71/4.asp
Nucleus of the cell
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DNA
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Directs the activity of the cell
Contains the information and instructions about
how the cell is built and its job
Is a chemical
Makes up the chromosomes
Nucleus send out instructions in the form of
chemicals through tiny openings in the
nuclear membrane
How do we see all this cool
stuff?
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In 1590 Zacharias Janssen was given
credit for developing the first
compound microscope.
A few years late, Anton van
Leeuwenhoek developed a lens that
could magnify up to 270 times!
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Later he was recognized as the first
person to observe microbial life.
Microscope Parts
1. ____eye piece_______
2. _______eye tube________________
14. ___Coarse Adjustment_______
13. ____ ___fine adjustment_____
3. _____objective disc___________
4. _____low powered objective____
5. _____ med. powered objective___
6. _____ high powered objective____
12. Arm _____________________
11. ____Base__________________
7. ______stage_________________
8. _____stage clip______________
9. ____slide_______________________
10. ____light source__________________
Microscope Safety
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Carry by the base and the arm
Check for shorts
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Does the light flicker on and off?
When you begin
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Clip the slide onto the stage
Check from the side to see where your lenses are
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Begin with the 4x at its highest position
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Turn the lens disc to the 10x
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focus
Focus
Move the lenses up a little bit before advancing to the 40x
How Cells Reproduce
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Terms
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Genes
Mitosis
Meiosis
How Cells Reproduce
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Most living things start out as a single cell.
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Not all of these cells develop into the same
type of cell.
Most living things do not grow at a
constant rate during their life time.
The only way for an organism
to grow is for cell reproduction.
http://www.agius.com/hew/resource/sens.htm
How Cells Reproduce
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DNA is the blueprint for the entire
organism.
DNA codes are used only when they
are needed
The nucleus contains the
chromosomes.
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The chromosomes contain the genes
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The genes are made of DNA
How Cells Reproduce
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http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Biochemistry/biochemi.htm
How Cells Reproduce
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In humans, there are
46 chromosomes in
all. (23 from each
parent)
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There are 50,000
genes for each
chromosome.
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Not all of these genes
are activated at all
times. This is called
differentiation.
http://www.alumni.ca/~laued3e/conclusion.html
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Mitosis
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Cell division that
produces new body
cells
http://www.dartmouth.edu/~cbbc/courses/bio4/bio4-1997/images/mitosis.JPG
http://www.micro.utexas.edu/courses/levin/bio304/genetics/celldiv.html
Meiosis
The process that forms reproductive cells
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmeiosis.html
http://www.biologie.uni-hamburg.de/b-online/e09/09b.htm
Variations in Organisms
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Most organisms are multicellular and
have genes from both parents.
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Due to the combining of cells that went
through meiosis
Traits that result from combining genes of
parents are: hair & eye color, height, left
or right handedness
How Traits are Inherited
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Terms:
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Sexual Reproduction
Dominant
Recessive
Punnett Square
George Mendel
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First person to show how traits are passed
from parents to offspring
Observed pea plants that he grew in his
garden
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Easy to get
Grew rapidly
Traits were easy to tell apart
Easy to cross different pea plants
Little chance for self pollination
Dominant and Recessive
Genes
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Mendel thought each plant carried two
factors for each trait that it showed.
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Parents make and pass on only one factor to the
offspring.
The offspring receives a factor from each parent
and so carries two factors for each trait.
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Factors may be the same or different
Factors may be dominant (stronger) or recessive
(weaker)
Punnett Squares
Used for making predictions
Chromosome Theory
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Chromosome theory states that
factors, which we know are genes, are
located on the chromosomes in very
specific places.