Unit #1 - Interdependence

1. Unit #1 - Interdependence What do living things need?

2. I. Studying Life Biology – the study of life (bios – “life”, -logy – “study of”). Biologist – someone who uses scientific methods to study living things.

3. A. Characteristics of Living Things All living things share the following : 1. Are made up of units called cells. Cell – a collection of living matter enclosed by a barrier that separates the cell from its surroundings. -Cells are the basic/smallest units of life. Unicellular – single-celled organisms. Multicellular – many-celled organisms.

4. Characteristics of Living Things 2. Can reproduce. Sexual – 2 parents create genetically different offspring. Asexual – one parent produces a clone of itself. 3. Are based on a universal genetic code : the molecule DNA.

5. Characteristics of Living Things 4. Growth and development. Metabolism – combination of chemical reactions in which an organism uses materials to carry out life functions. 5. All obtain & use materials & energy. 6. All respond to their environment. Stimulus – a signal to which an organism responds; can be internal or external.

6. Characteristics of Living Things 7. Maintain a stable internal environment. Homeostasis – process by which an organism keeps its internal conditions fairly constant in order to survive. 8. In general, they change over time.

7. B. Other Branches of Biology 1. Zoology – study of animals. 2. Botany – study of plants. 3. Paleontology – study of ancient life.

8. C. 4 types of organic molecules in living things : 1. Carbohydrates – compounds made up of carbon, hydrogen, & oxygen atoms, usually in a ratio of 1 :2 :1, ex : sugars, starches, & cellulose. **Living things use carbohydrates as their main source of energy.** -Energy for cell activities comes from the immediate break-down of sugars, such as glucose. -Extra sugar is stored as complex carbohydrates known as starches.

9. Lipids 2. Lipids – macromolecules made mainly from carbon & hydrogen atoms & glycerol; includes fats, oils, waxes, phospholipids, & steroids. -Used to store energy, insulate, repel water, & form membranes.

10. Nucleic Acids 3. Nucleic acids – macromolecules containing hydrogen, oxygen, nitrogen, carbon, & phosphorous. -Contain genetic/hereditary info. -Are assembled from nucleotides – monomers of nucleic acids made up of a : 1. 5-carbon sugar 2. Phosphate group 3. Nitrogenous base.

11. 2 Major Types of Nucleic Acids : A. DNA – (deoxyribonucleic acid) carries instructions that control the activities of a cell. B. RNA – (ribonucleic acid) uses those instructions to make/build proteins.

12. Proteins 4. Proteins – macromolecules that contain nitrogen, carbon, hydrogen, & oxygen. -Are made up of amino acids – compounds with an amino group (-NH2) on one end & a carboxyl group (-COOH) on the other end. -Amino acids are the building blocks of proteins. -20 different amino acids are used to build proteins. Different combinations = different proteins.

13. Each protein has a specific role, ex : 1. Control the rate of reactions & regulate cell processes. 2. Form bones, muscles, & hormones. 3. Transport substances in or out of cells & fight disease : antibodies. Enzymes – proteins that help control chemical reactions. Can speed up reactions, ex : Digestion.

14. D. Other nutrients needed by living things Nutrients– substances in food that provide the raw materials and energy the body needs for essential processes. Nutrients are keep the body’s cells functioning, growing, and replicating. -Are made up of chemical elements including carbon, oxygen, hydrogen, nitrogen, and phosphorous.

15. Vitamins 1. Vitamins – chemical compounds needed by the body in small amounts to strengthen the immune system, grow, and repair damaged cells/tissues. -Vitamins are supplied to the body by a well balanced diet.

16. Problems related to vitamin deficiency : Vitamin A – Liver problems, hair loss, rough skin. Carrots are a good source. Vitamin B2 – Eye problems and cracking skin. Vitamin B3 – Mental problems, rash, and diarrhea. Vitamin C – Sore mouth, bleeding gums, and bruises. Vitamin D – Bowed legs, rickets, & poor teeth.

17. Minerals 2. Minerals – chemical compounds needed in small amounts to help form important cell parts. -Mineral deficiency can cause : a. Iron – used for blood. Risk = Anemia, which causes extreme fatigue & bruising. b. Calcium – used for strong bones and teeth. Risk = Osteoporosis later in life. c. Magnesium – used for bones and teeth. Risk = Severe muscle twitches that can become very painful. d. Iodine – used for making chemicals in the thyroid (found in salt). Risk = development of a goiter (abnormally enlarged thyroid). e. Sodium – (NaCl or salt) used for muscle contractions and nerve messages.

18. Water 3. Water – fluid made up of hydrogen and oxygen that makes up approximately 50-60% of the human body. How much water does the average adult need? Answer : 2 liters per day (8 glasses) The body uses water to : • Re-hydrate the body by replenishing liquids. • Flush out toxins. • Control body temperature.