Chapter 1

Biology

The science of life

Biologists

Scientist who studies life

Observation

The act of viewing the world around us

Experimentation

A disciplined and controlled way of asking and answering questions about the world in an unbiased manner

Hypothesis

Allows for tentative explanations. It must have a reasonable explanation but its not correct until tested

Controlled experiment

A scientific test where only one variable (the independent variable) is manipulated at a time, while all other factors are kept constant. It one of the most powerful types of experiments

Variable

A condition/treatment that is different in one group of the experiment

Test group

The group when the variable is introduced to

Control group

The group that remains unchanged

Exploration

• Make observations

• Ask questions

• Approach the world with curiosity

Investigation

• Formulate hypothesis/models

• Make predictions

• Do experiments/make new observations

• Gather and interpet data

• Establish a theory

Communication

• Discuss experiments

• Share results

• Publish papers

• Participare in conferences

• Inform policies

• Address problems

Theory

A general explanation of the world supported by a large body of experiments and observations

Metabolize

Taking energy from their environment and use of those reosurces to grow

Characteristics of living things

1. Grow and reproduce

2. Harvest transform and use energy and chemical budling blocks

3. Regulate the internal environment

4. Genetic material

5. Consist of one or more cells with organelles

6. Responds to the environment around them

7. Evolve

First law of thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Second law of thermodynamics

The degree of disorder in the universe tends to increase

Entropy

The amount of disorder

Cell

The simplest entity that can exist as an independent unit of life

Cell membrane

Separates the living material within the cell from the nonliving environment around it

Nucleus

The compartment of the cell that houses the DNA in chromosomes

Cytoplasm

The entire contents of the cell is enclosed by the cell membrane but outside the nucleus, if present

Prokaryote

Cells without a nucleus

Eukaryote

Cells with a nucleus

Bacteria

Consists of single celled organism without a nucleus. They have a cell wall made of peptidoglycan

Archaea

Consist of single celled organisms with a singular circular chromosome and lacking a membrane bound nucleus

Eurkaya

Cells have a nucleus and divided by mitosis

DNA

The principle molecule of biological heredity. A polymer of nucleotides

RNA

Related to DNA, synthesized as a complement to its DNA template, and involved in protein synthesis, among other functions

Protein

The key structural and functional molecule that does the work of the cell, providing structural support and catalyzing chemical reactions

Transcription

The synthesis of RNA from a DNA template

Translation

The synthesis of proteins from an RNA template

Central dogma

The observation that information in a cell usually flows from DNA to RNA to protein

Gene

The DNA sequence that corresponds to a functional product, such as protein

DNA replication

Allows genetic information to be passed from generation to generation

Mutations

An error in replication or a mutagen, like radiation/chemicals

Metabolism

Describes chemical reactions by which cells convert energy from one form to another and build/break down molecules

ATP

The process releasing energy stored in chemical form. Provides a readily accessible form of chemical energy

Evolution

Change in the genetic makeup of a population over time

Natural selection

The process by which organisms with favorable traits are more likely to survive and reproduce, passing those traits on to their offspring

Environmental variation

Variation among individuals that is due to differences in the environment

Genetic variation

Differences in genotype among individuals in a population

Descent with modification

Evolutionary changes that have accumulated over time since two lineages split

Dependent variable

What you’re measuring in the study

Ex. number of eggs per week, fish dna

Independent variable

What is being manipulated in the experiment/cause

Ex. Chicken feeder

Prediction

An expected outcome based on the hypothesis