Introduction to Biology

Scientific Method

a process used during a scientific investigation to answer a scientific question

Hypothesis

explanation for a particular fact. The hypothesis needs to be verified or falsified based on collected evidence. All studies must have at least one hypothesis, but a researcher may come up with many hypothesis if more than one explanation could answer the question.

Data

the facts, statistics and calculations used in scientific analysis

Independent Variable

are variables that scientists control to test the effects on the dependent variables. Ideally, there's only one independent variable in each experiment. In the example, the amount of coffee becomes the independent variable.

Dependent Variable

are variable affected by the changes made to the independent variable. In the example, blood pressure and changes in the heart are dependent variables

Scientific Theory

When repeated experimentation supports a hypothesis over a long period of time, it can become a scientific theory. Some people have a misconception that theories turn onto laws after extensive research. A theory is a well-supported explanation of why a phenomenon occurs

Scientific Law

is a scientifically acknowledged principle that's been confirmed by repeated experimental observations

Validity

the extent to which a measurement, test or study measures what it is said to measure

Introduction to Biochemistry

Matter

anything that occupies space and possesses mass

Atoms

The basic units of matter

Proton

Positive part of an atom

Electron

Negative part of an atom

Neutron

Part of an atom that has no charge

Element

One of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances are primary constituents of matter.

Molecule

Group of atoms bonded together representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Compound

composed of two or more separate chemical reaction

Chemical Reaction

an interaction between molecules that cause a chemical change, converting existing substance into a new substance

Carbohydrates

Starches and sugars that are the main energy source for living things

Lipids

Fats, waxes, and steroids that are not soluble in water

Nucleic Acids

DNA found in the nucleus and RNA found in the cytoplasm

Proteins

Made up of one or more amino acids. Have many different functions.

Amino Acids

The building blocks of proteins.

Cells: The basic unit of life?

Homeostasis

The process where organisms maintain an internal balance

Eukaryote

a cell that has a defined nucleus

Nucleus

Nucleus

The command center of the cell. DNA is located here. It is enclosed by a membrane called the nuclear membrane.

Prokaryote

The oldest form of life on Earth. Lack a defined nucleus.

Cytoplasm

Mostly water and salt and it suspends the organelles within the cell

Cytoskeleton

Support network of protein fibers that form a framework for the cell.

Cell Wall

Made of cellulose to provide structure and strength to the cell

Chloroplasts

Contain chlorophyll for the process of photosynthesis

Mitochondria

Rod shaped organelles throughout the cell that convert food into energy for the cell

Vacuole

Storage centers to nutrients or wastes for the cell

Ribosomes

Make proteins for the cell

Endoplasmic Reticulum

Golgi apparatus

Receives proteins and lipids from the ER and packages, sorts and places in vesicles for the cell

Two types, Rough ER- has ribsomes and process proteins and Smooth ER- has no ribosomes and produces lipids..

Lysosome

Digestion organelles of the cell. Break down big molecules into smaller molecules that the cell can use or excrete

Centriole

Pair of cylindrical tubules that play an important role in cell division

Cilia & Flagella

Hairlike structures that extend from the surface of the cell

Plasma Membrane

Flexible boundary forming the outside of the cell. Also called the cell membrane

Cell Transport and Homeostasis

Passive Transport

Movement of molecules across a barrier without using energy.

Diffusion

The movement of one substance from an area of high concentration to an area of low concentration.

Osmosis

The movement of water molecules across a semipermeable membrane.

Solute

Substance in a solution that is dissolved.

Solvent

Substance in a solution that dissolves the other substance.

Hypertonic

Concentration of solutes is greater outside of the cell than inside. Water moves form inside the cell out.

Hypotonic

Concentration of solutes is lower outside the cell than inside.Water moves from the outside of the cell in.

Isotonic

The concentration of solute is the same inside the cell as outside. Water moves equally into and out of the cell.

Facilitated Diffusion

Diffusion that requires the help of proteins in the membrane to take molecules in and out of the cell.

Active Transport

REquires the cell to use energy to move molecules from low concentration to high concentration.

Endocytosis

Takes place when the plasma membrane folds around or surrounds the molecule moving into the cell, forming a vacuole.

Exocytosis

TAkes place when a golgi apparatus packs large molecules into transport vesicles that travel and fuse with the plasma membrane.

The cell Cycle and Eukaryotic Cell division

Mitosis

Division of the cell

Cytokinesis

Division of the cytoplasm

Chromatid

One of two identical "sister" parts of a duplicated chromosome

Centromere

Area where the chromatids are attached

Interphase

The period of growth between cell divisions

Cell cycle

The series of events that cells go through as the grow and divide

Prophase

First and longest phase of mitosis.  The chromosomes become visible and the centrioles separate and move to opposites sides of the cell.

Centriole

Two tiny structures located in the cytoplasm near the nuclear envelope

Spindle

A fan like microtubule structure that helps separate the chromosomes

Metaphase

Second phase of mitosis. Chromosomes line up across the center of the cell.

Anaphase

The third phase of mitosis.  The centromeres that join the sister chromatids split, allowing the sister chromatids to separate and become individual chromosomes.  The continue to move until they have separated into two groups near the poles of the spindle

Telophase

The fourth and final phase of mitosis.  The chromosomes begin to disperse into a tangle of dense material.

Meiosis

Homologous

Each chromosome that came from the male parent has a partner that came from the female parent

Diploid

A cell that contains both sets of homologous chromosomes. Means 2 sets

Haploid

A cell that contains only a single set of chromosomes. Meaning one set