Introduction to biology

Scientific Method

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

Hypothesis

an 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 hypotheses 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 variables 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 into laws after extensive research.  A theory is a well-supported explanation of why a phenomenon occurs

Scientific law

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 into laws after extensive research.  A theory is a well-supported explanation of why a phenomenon occurs

Validity

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

Negative part of an atom

Element

One of more than one hundred substances that cannot be chemically inter converted or broken down into simpler substances and 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 elements

Chemical reaction

an interaction between molecules that causes 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

Protein

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

Amino Acid

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

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 hold nutrients or wastes for the cell

Ribosomes

Make protein for the cell

Endoplasmic Reticuluma

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

Golgi apparatus

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

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 and 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 is dissolved

Hypertonic

concentration of solutes is greater outside of the cell than inside. water moves from 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 they 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 fanlike 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: Cell Division for Reproduction

Homologous

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

Diploid

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

Haploid

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