Notes for 9/10/07
Animal and Plant Cells
Animal and plant cells have several parts in common.
They both have a nucleus that controls the cell’s activities.
They both have vacuoles that store food, water, and waste.
They both have a thin outer coating called a cell membrane.
Only plant cells have cell walls.
Plant cells have cell walls to hold the plant up.
You do not need cell walls because you have a skeleton.
Plant cells also contain chlorophyll.
Chlorophyll is kept in the chloroplasts.
Chlorophyll is what the plants use to get energy from the sun.
When plants get energy from the sun it is called photosynthesis.
Why aren’t you green?
Why don’t you have cell walls?
Source: Harcourt Science 2000, pp A8-A9
Notes for 9/12/07
Cells, Tissues, Organs, Organ Systems
When food and water pass through the cell membrane it is called osmosis.
Osmosis is a special kind of diffusion.
Organisms with many cells usually have many different kinds of cells.
Similar cells work together.
Cells that work together to perform a specific function form a tissue.
Humans have 4 different kinds of tissue.
Tissues that work together form an organ.
Organs that work together to perform a function form an organ system.
Source: Harcourt Science 2000, A12-A13
Notes for 9/17/07
How Organisms Grow
1. We learned the nucleus of the cell controls the cells activities.
2. The nucleus controls the cells activities with chromosomes.
3. Humans have 46 chromosomes in the nucleus of their cells.
4. You get half of your chromosomes from your mother and half from your father.
5. Remember we learned all living things must grow.
6. Living organisms grow by cell division called mitosis.
7. One cell divides and becomes two cells.
8. You began life as one cell called a zygote and your one cell became two, two became four, four became eight, and so on.
9. Even during growth each human cell still has 46 chromosomes.
10. Regeneration is when cells grow again. You have experienced this when you have injured your skin and it healed.
11. Some living organisms do not need two parents to reproduce.
12. When it is time for them to reproduce they simply divide.
Source: Harcourt Science, 2000, A38-A42
Notes for 9/19/07
Stages of Life
1) Living organisms have a life cycle. Some life cycles are very short (minutes, bacteria). Some life cycles are very long (decades, trees).
2) Most life cycles begin with a young organism struggling to survive.
3) Some organisms are born alive. Some hatch from eggs.
4) Some organisms sprout from seeds or spores.
5) Most organisms mature to full size and form. This is called the adult stage.
6) During the adult stage organisms can reproduce.
7) Some organisms look like their parents when they are born. (Humans)
8) Some organisms do not resemble their parents when they are born. (Meal worms, butterflies)
9) Organisms that change body shape and size as they mature undergo metamorphosis. (Big change)
10) Butterflies are hatched from an egg and mature as a caterpillar (larva).
11) As the larvae grow they form a cocoon (pupa).
12) After a while the adult butterfly comes out of the cocoon.
13) The adult butterfly can then lay eggs to form future butterflies.
Source: Harcourt Science, A46-A49
Notes for 9/21&24/07
Inherited Traits
1) You have 46 chromosomes in the nucleus of your cells.
2) You received 23 chromosomes from your mother and 23 from your father.
3) Your chromosomes are also called your genes.
4) Your chromosomes control many of your inherited traits.
5) Your inherited traits are your hair color, eye color, skin color, nose and ear shape, tongue rolling and more.
6) All of us have dominant traits we can see and recessive traits we can’t see.
7) Punit Squares-
Source Harcourt Science, 2000, A52-A53