Life Science

Chapter 3- Cell Processes

Chemistry- every natural process occurring inside our bodies is chemistry; reactions between numerous chemicals which create new chemical to help our body metabolize- do the processes of life.

Matter: has two characteristics:

1. Mass -the amount of material in the object

2. Volume- the amount of space an object takes up.

Atom is the basic unit of matter. It has two regions: the nucleus and the electron cloud.

It is composed of 3 types of particles (called sub atomic particles).

1. Positively charged protons located in the nucleus.
2. Negatively charged electrons located in the electron cloud
3. Neutral charged neutrons located in the nucleus.

Elements: particular types of atoms-(about 90 occur in nature.

Examples: hydrogen, oxygen, see table

Combinations of elements are called compounds: they are formed when two or more elements combine their electron clouds, their nuclei remain separate. All chemistry occurs within the electron cloud Water (Hydrogen and oxygen)

Two ways they can combine:

1. by sharing electrons; hydrogen and oxygen share their combined electrons, with most of the electrons are with the oxygen atom. This is called a covalent bond.

Molecule: the smallest part or unit of a compound.

Mixture: combination of elements or compounds that do not mix chemically; they retain there own characteristics, they do not combine chemically --example would be fruit salad.

Types of mixtures:

b. suspension- a mixture that swill separate on its own if left to settle, blood, sand and water.

Organic Compounds :any compound that contains carbon

1. Carbohydrates made of carbon, oxygen, and hydrogen. Ex. Sugar, starch,

a. provides energy and also is good way to store energy

b. As a building block- cellulose, a starch in plants

2. Lipids- made of carbon, oxygen, and hydrogen; ex., Fats, Oils and Waxes

a. store and provide energy

b. some structural functions.

3. Proteins-are build of amino acids which are made of carbon, oxygen, hydrogen, and nitrogen.

a. primary building blocks of all cells

b. used in most chemical processes that happen within the cell.

4. Nucleic Acids- large organic molecules made of carbon, oxygen, hydrogen, nitrogen, and phosphorus. Ex. DNA and RNA

a. provide directions (genetic code) that controls all cell functions

b. DNA in chromosomes, RNA in mitochondria, chloroplasts, and nucleus

Definition- taking in or releasing materials to/from the cell.

Taking in: food, water, oxygen, and nutrients

Releasing waste (CO₂ and other wastes from cell processes.

Mechanisms:

1. Cell Membrane: is permeable- lets very small particles pass in and out (like a fish net)

Passive transport- doesn’t require energy

a. Diffusion- when a lot of the same material is together (crowded) some moves to where there is little of the material around until equilibrium is reached (even distribution) Ex. Perfume in the air, dye in water

b. Osmosis- the diffusion of water through the cell membrane.

Plasmolysis-

Active Transport: energy is required to move materials in and out of cells.

a. materials move from small concentration to a large concentration

Ex.

b. types- 1. endocytosis- movement of materials into the cell

2. exocytosis- movement of materials out of the cell

Energy is obtained from food

a. Photosynthesis- light energy is changed into chemical energy.

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b. Respiration- part of metabolism , chemical activities that keep an organism alive

1. consumers eat producers to obtain chemical energy and tohter nutrients. Some consumers eat other consumers. This is a FOOD CHAIN ( food chains are ways to identify how energy flows in a community of living things)

2. during respiration, food is broken down and energy is released.

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3. Fermentation- a special kind or respiration when no oxygen is present

a. lactic acid is produced. It makes your muscles sore.

b. energy is produced, but far less then respirations

c. yeast and some bacteria use fermentation.

Biomass (organic materials)