Biology Chapter 1-2 Themes & Concepts in Biology

Chapter 1: The Study of Life

What is Biology?

The study of living organisms, divided into many specialized fields that cover their morphology, physiology, anatomy, behavior, origin, and distribution.

“Bio” Greek word Bios

Living organisms share key characteristics that define life and differentiate them from non-living entities

Properties that define life

Order, response to stimuli, reproduction, growth, development, adaptation/evolution

Are viruses alive?

Yes, viruses are alive

Molecules

Building blocks of life, including proteins, nucleic acids, and lipids

Cells

Basic unit of life, where metabolic processes and function occurs

Organisms

An individual living plant animal or single-celled life form. Don’t forget that bacteria and archaea are organisms composed of a single cell.

Ecosystems

Communities of organisms interacting with each other and their physical environment

How many domains in diversity of life?

3 domains

Prokaryotes entail:

Eubacteria and Archaea

Eukaryotes entail: 

Only Eukaryotes

Kingdoms

In each domain life is further divided into groups that highlight unique characteristics and functions in ecosystems

Evolutionary Relationships

The evolutionary tree illustrates the relationships between organisms, showing how species have evolved and diversified over time

Process of Science

Ask a question form a hypothesis, conduct and experiment, analyze results

What does Biology primarily study?

Living organisms and their interactions from molecular structure and function of cells, to evolution growth, and distribution of organisms along with their complex relationships within ecosystems and environments

Eukarya

the domain that includes all multicellular organisms (and some single celled too)

What falls under Eukarya domain?

Plants, fungi, protists

Order as a property of life

Reflects how living organisms maintain structured complexity

Insulin

Peptide hormone essential for regulating blood glucose levels enabling cells to absorb and use sugar for energy, and maintaining metabolic balance in the body

Structure of Atoms

Smallest unit of matter and cannot be subdivided into smaller substances. They interact for form molecules

Chemistry

Study of interactions between atoms and molecules

How many essential elements are needed for an organism to live and reproduce?

20-25% of the 92 naturally occurring elements

What elements comprise of 96% of living matter?

Hydrogen, Carbon, Nitrogen, Oxygen

Electrons

Negatively charged particles

Protons

Positively charged particles

Neutrons

Uncharged particles

What subatomic particle make up the nucleus?

Protons and neutrons

Where to electrons move around?

In orbit around the nucleus/ “shells”

Isotope

Atoms with different number of neutrons

Energy

Capacity to cause change

Potential energy

Energy that matter has because of its location or structure

Electron shell

An electron’s state of potential energy called energy level

Electron Configuration

Electrons are arranged in electron shells, each corresponding to a different energy level

Energy levels based on shells

First/lowest shell has the lowest energy level, highest energy level in the highest shell

Valence

Number of missing or extra electrons in the outermost shell

Why do molecules hold together?

the valence electrons of the combining atoms form attractive forces, called chemical bonds, between the atomic nuclei

What influences the reactivity of an atom?

The number of electrons in the outer valence shell

Shell 1

Holds 2 electrons

Shell 2

Holds 8 electrons

Shell 3

Holds 8 electrons as well

Compounds

Molecule that contains two or more kinds of atoms

Ionic bonds

Attraction between ions of the opposite charge and are charged atoms that have gained or lost electrons

Cations

Atoms that lose electrons and become positively charged

Anions

Atoms that gain electrons and become negatively charged ions

Covalent bonds

When two atoms share one or more pairs of electrons and are stronger and more common in organisms than ionic bonds

Hydrogen bonds

Form when a hydrogen atom that is covalently bonded to an O or N atoms is attracted to another N or O atom in another molecule

Intermolecular force

Force that is weaker than covalent and ionic bonds

Van der Waals interactions

When transiently positive and negative regions of molecules attract each other. They are weak bonds but allow geckos to stick on walls.

Chemical reactions

Involves the making or breaking of bonds between atoms and a change in chemical energy occurs during this reaction

Endergonic

reactions that absorb energy

exergonic

Reactions that release energy

Synthesis reactions

When atoms, ions, or molecules combine to form new, larger molecules

Anabolism

Synthesis of molecules in a cell

Decomposition reaction

when a molecule is split into smaller molecules, ions or atoms

Catabolism

decomposition reactions in a cell

Synthesis Reaction

Decomposition Reaction

Exchange reaction

Part synthesis and part decomposition

Exchange reaction

Water

Polar molecule, powerful solvent, temperature moderation, cohesive behavior, density

Properties of water that make it essential for life

It is inorganic polar molecule that has an unequal distribution of charges

What happens too an ionic compounds when dissolved in water?

each ion is surrounded by a sphere of water molecules

Acids

Substances that dissociate into one or more hydrogen ions and one or more negative ions

Bases

Substances that dissociate into one or more hydroxide ions and one or more positive ions

Concentration of H+

expressed as pH

What pH do most organisms grow best between?

pH 6.5 and 8.5