In preparation for next Thursday's tentatively scheduled science test, here are my notes:Sec. 4-1: What is life?
I. Characteristics of living things
A. organisms- living thing
1. all living things are made of cells
2. all living things contain similar chemicals
3. all living things use energy
4. all living things grow and develop
5. all living things respond to their surroundings
6. all living things can reproduce
B. Cellular organization
1. cell- basic unit of structure and function in an organism
2. structure- the way it is made
3. function- job it performs
C. chemicals of life
1. water
2. proteins
3. lipids
4. carbohydrates
5. nucleic acids
D. Energy Use
1. grow
2. repair
E. Growth & Development
1. create new cells
2. more complex over time
F. Response to surrounding
1. stimulus- a change in an organism’s surroundings that causes the organism to react
2. external stimuli- comes from the outside
3. internal stimuli- come from within the organism
4. response- an action or change in behavior
G. Reproduction- produce offspring that are similar to the parents
II. Life Comes from Life
A. spontaneous generation- mistaken idea that living things arise from nonliving sources
III. The Needs of Living things
A. Energy
1. Autotrophs- organisms that make their own food
2. heterotrophs- organisms that can not make their own food
B. Water
C. Living space
1. competition- organisms may compete for living space
2. Share living space
D. Stable internal conditions
1. homeostasis- the maintenance of stable internal conditions despite changes in the surroundings
Sec. 2 Discovering Cells
I. First Cell Sightings
A. Microscope made it possible for people to discover and learn about cells
1. microscope- instrument that makes small objects look larger
2. compound microscope- a light microscope that has more than one lens
B. Robert Hooke- one of the first people to observe cells
C. Anton van Leeuwenhoek- observed tiny objects with microscope, such as bacteria
D. Matthias Schleiden - concluded plants are made of cells
E. Theodor Schwann- concluded animals are made of cells
II. Cell Theory
A. All living things are composed of cells
B. Cells are the basic unit of structure and function in living things
C. All cells are produced from other cells
IV. How a Light Microscope Works
A. Magnification- ability to make things look larger than they are
1.lens or lenses in a light microscope magnify an object by bending the light that passes through them
2.compound microscope uses 2 or more lenses
B. Resolution
1. the ability to clearly distinguish the individual parts of an object
2. sharpness of an image
V. Electron Microscopes
A. Use a beam of electrons instead of light to examine a specimen
B. Much higher resolution than light microscopes
Sec. 3 Looking Inside Cells
I. Organelles- tiny cell structures
II. Cell Wall- a rigid layer of nonliving material that surrounds the cells of plants and some other organisms
A. Made of cellulose
B. Plants & other organisms have cell walls
C. Animal cells lack cell walls
D. Protects & supports the cell
III. Cell Membrane
A. located just inside the cell wall
B. forms the outside bounder that separates the cell from its environment in animals
C. controls what substances come into and out of a cell
IV. Nucleus
A. Nucleus- cell’s control center, or “brain”, directing all of the cell’s activities
B. Nuclear Membrane- protects the nucleus
C. Chromosomes
1. Chromatin-thin strands in the nucleus containing genetic material
2. chromosomes- structures formed when chromatin strands coil and condense
C. Nucleolus
1. located in the nucleus
2. where ribosomes, organelles where proteins are produced, are made
V. Organelles in the Cytoplasm
A. Cytoplasm- the region between the cell membrane and the nucleus
B. Produce energy, build and transport needed materials, and store and recycle wastes
C. Mitochondria
1. power houses
2. produce most of the energy the cell needs
D. Endoplasmic reticulum- maze of passageways that carry proteins and other materials from one part of the cell to another
E. Ribosomes- grainlike bodies that produce proteins
F. Golgi Bodies-
1. flattened collection of sacs and tubes that receive proteins and other newly formed materials from the endoplasmic reticulum, package them, and distribute them to other parts of the cell.
2. mail center of the cell
3. Also release materials outside the cell
G. Chloroplasts
1. large green structures floating in the cytoplasm
2. capture energy from sunlight and use it to produce food for the cell
3. give plants their green color
H. Vacuoles
1. large, round, water-filled sac floating in the cytoplasm
2. storage area of the cellstores food and other materials needed by the cell
3. Can also store waste products
I. Lysosomes
1. small round structures that contain chemicals that breakdown large food particles into smaller ones
2. break down old cell parts and release the substances so they can be used again
3. cell’s cleanup crew
VI. Bacterial Cells
A. No nucleus
B. Prokaryotes- organisms that do not contain a nucleus
C. Eurkaryotes- organisms whose cells contain a nucleus and many of the organelles
VII. Structure and Function in Cells
A. Cells in many complex organisms are specialized
1. muscle cell
2. nerve cell
3. blood cell
VIII. Levels of organization
A. Bodies of many multi-cellular organisms have four levels of organization
1. cells
2. tissues- a group of cells that performs a specialized function
3. organs- a group of tissues that perform a specific function
4. organ systems- a group of organs that perform a complex function
5. population- all the members
B. Cells – tissues- organs- organ systems- organisms- populations
Sec. 4: Intro to Genetics
I. Parents to Offspring
A. Heredity- the process by which traits pass from parents to offspring
B. Organisms resemble their parents because they inherit genetic material from their parents
C. Genetic material is contained in cells
D. Genetics- scientific study of heredity
II. Role of Genes in Inheritance
A. DNA- the genetic material that carries information about an organism that is passed from parents to offspring
B. Genes- a section of DNA that controls a trait that an organism inherits
III. Asexual and Sexual reproduction
A. Asexual reproduction-
1. productive process that involves only one parent
2. offspring have genes identical to those of the parent
B. Sexual reproduction
1. new organisms result from the combination of genetic material from two parent organisms
2. sperm- male sex cell
3. egg- female sex cell
4. traits of the new organism are determined by genetic material from both the male and the female parents
IV. Sexual Reproduction and Change- organisms change from generation to generation as genetic material is re-sorted, over and over, each time reproduction occurs
V. Changing Traits by selective breeding
A. selective breeding- technique used to improve the quality of organisms by selecting, or choosing, certain organisms for reproduction
B. organisms w/ certain traits are mated to produce offspring with the desired traits of both parents
C. desired traits are produced by the combination of genetic material that the offspring inherit from both of their parents
VI. Changing Traits in Nature
A. Traits of organisms can change over generations naturally
B. Changes help can help organisms survive better in their environments
