Understanding Living Things Cells, Genetics, and Heredity Mrs. Strand 6th grade Lockwood Middle School Harcourt Science Chapter 1

Cells, Genetics and Heredity Terms Cell membrane Cell wall Cytoplasm Mitochondria Chloroplast Vacuole Nucleus Chromosome Nuclear Membrane

How Plants & Animal Cells Differ The discovery of cells Robert Hooke 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 Cells are the basic building blocks of all living things Large organisms have more cells that can do different things All live activities take place in cells Heart, lungs, kidneys, skin… New cells are only produced by existing cells

How Plants & Animals Differ http://www.beyondbooks.com/lif71/4.asp

Nucleus of the cell DNA 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? 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! Later he was recognized as the first person to observe microbial life.

Microscope Parts ____eye piece_______ 2. _______eye tube________________ 3. _____objective disc___________ 4. _____low powered objective____ 5. _____ med. powered objective___ 6. _____ high powered objective____ 7. ______stage_________________ 8. _____stage clip______________ 9. ____slide_______________________ 10. ____light source__________________ 14. ___Coarse Adjustment_______ 13. ____ ___fine adjustment_____ 12. Arm _____________________ 11. ____Base__________________

Microscope Safety Carry by the base and the arm Check for shorts Does the light flicker on and off? When you begin Clip the slide onto the stage Check from the side to see where your lenses are Begin with the 4x at its highest position focus Turn the lens disc to the 10x Focus Move the lenses up a little bit before advancing to the 40x

How Cells Reproduce Terms Genes Mitosis Meiosis

How Cells Reproduce Most living things start out as a single cell. 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 DNA is the blueprint for the entire organism. DNA codes are used only when they are needed The nucleus contains the chromosomes. The chromosomes contain the genes The genes are made of DNA

How Cells Reproduce http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/Biochemistry/biochemi.htm

How Cells Reproduce In humans, there are 46 chromosomes in all. (23 from each parent) There are 50,000 genes for each chromosome. Not all of these genes are activated at all times. This is called differentiation. http://www.alumni.ca/~laued3e/conclusion.html

Mitosis 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 Most organisms are multicellular and have genes from both parents. 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 Terms: Sexual Reproduction Dominant Recessive Punnett Square

George Mendel First person to show how traits are passed from parents to offspring Observed pea plants that he grew in his garden 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 Mendel thought each plant carried two factors for each trait that it showed. 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. Factors may be the same or different Factors may be dominant (stronger) or recessive (weaker)

Punnett Squares Used for making predictions

Chromosome Theory Chromosome theory states that factors, which we know are genes, are located on the chromosomes in very specific places.