General Biology Unit 1

chapters 1,2,3,4,5

What is biology?

is the scientific study of life.

What are the characteristics of life?

order, regulation, evolutionary adaptation, reproduction, energy processing, environmental response, and growth and development.

Unifying Themes in Biology

Organization, Information, Energy and Matter, Interactions, and Evolution.

What are the levels of biological organization from smallest to largest?

Molecules, Organelles, Cells, Tissues, Organs, Organisms, Populations, Communities, Ecosystems, Biosphere

What are emergent properties?

result from the arrangement and interaction of parts within a system.

How are structure and function related in biological organization?

Structure and function are correlated at all levels of biological organization.

What is the smallest unit of organization that can perform all activities required for life?

cell

What encloses cells and regulates material passage?

cell membrane

What is the main difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus and no membrane-bound organelles, while eukaryotic cells have membrane-enclosed organelles

What is the genetic material found in chromosomes?

DNA

What do genes encode?

Information for building molecules and directing organism development

What is the role of genes in protein synthesis?

Genes provide the blueprint for making proteins.

What is the process of gene expression?

DNA is transcribed into RNA, then translated into proteins.

Energy and Matter

Life requires energy transfer and transformation. Chemical energy from producers is passed to consumers, sustaining life.

Interactions in Biological Systems

ensure smooth integration of system components. Feedback mechanisms like negative and positive feedback are common.

What is positive feedback?

A type of regulation that responds to a change in conditions by initiating responses that will amplify the change.

negative feedback

a mechanism of response in which a stimulus initiates reactions that reduce the stimulus

How does positive feedback affect an organism?

It takes the organism away from a steady state.

Evolution

Evolution explains life's unity and diversity.

Three domains of life

Bacteria, Archaea, Eukarya

What is DNA?

The universal genetic language common to all organisms.

.How does DNA demonstrate unity in cell structure?

It is common across diverse life forms.

scientific inquiry

Science involves seeking explanations through observations, hypotheses, and testing, aiming to understand natural phenomena.

qualitative data

descriptive data

quantitative data

numerical data

Inductive Reasoning

draws conclusions based on repeated observations, leading to generalizations.

Hypotheses

are testable predictions based on observations.

experiments

test hypotheses under controlled conditions

Deductive Reasoning

uses general premises to make specific predictions.

scientific hypothesis must be

testable and falsifiable

Science vs. Non-Science

Supernatural and religious explanations lie outside the realm of science.

Experimental Variables

Controlled experiments compare experimental and control groups, with independent and dependent variables.

Theories in Science

are broader than hypotheses, supported by evidence, and can lead to new testable hypotheses.

What does technology apply?

scientific knowledge for specific purposes.

What does science aim to understand?

natural phenomena

Matter

comprises chemical elements and compounds, occupying space and having mass.

Element

are substances that cannot be broken down into other substances by chemical reactions.

Compound

consist of two or more elements in fixed ratios, with properties different from the elements.

What percentage of natural elements are essential for life?

About 20-25%

Which elements comprise 96% of living matter?

Carbon, hydrogen, oxygen, and nitrogen

Trace Elements

are needed in minute quantities by organisms.

Atom

are the smallest units of matter that retain element properties.

Subatomic Particles

Atoms consist of

neutrons

the particles of the nucleus that have no charge

protons

positively charged subatomic particles

electrons

negatively charged subatomic particles

Atomic Nucleus

Neutrons and protons form the nucleus, while electrons surround it with a negative charge.

Atomic Number

is the protons in its nucleus.

Mass Number

is protons plus neutrons, approximating the atomic mass.

What are isotopes?

Atoms of an element with the same protons but different neutrons.

What happens to isotopes over time?

Isotopes decay, emitting particles and energy.

Radioactive Tracers

are used in medicine and imaging as diagnostic tools.

What determines an atom's chemical behavior?

Electron distribution in shells

How is electron capacity organized in an atom?

Each shell has a specific electron capacity

What do valence electrons determine?

An atom's chemical behavior

How do full shells affect chemical behavior?

They lead to chemical inertness

Chemical Bonds

Atoms share or transfer valence electrons, forming chemical bonds that hold atoms together.

Covalent Bond

involves sharing a pair of valence electrons between atoms, contributing to molecule formation.

What is a single covalent bond?

The sharing of one pair of valence electrons.

What is a double covalent bond?

The sharing of two pairs of valence electrons.

What does a structural formula represent?

Atoms and bonding in a molecule

Give an example of a structural formula.

H—H for a covalent bond between hydrogen atoms

How can a molecular formula be further abbreviated?

As H₂

Nonpolar Covalent Bond

Electrons are shared equally

Polar Covalent Bond

One atom is more electronegative, leading to unequal electron sharing and partial charges

What is an ionic bond?

An attraction between ions, formed by electron transfer, resulting in positively charged cations and negatively charged anions.

What are the components of an ionic bond?

Positively charged cations and negatively charged anions formed by electron transfer.

What atoms are involved in a hydrogen bond?

Hydrogen atom covalently bonded to an electronegative atom and another electronegative atom, often oxygen or nitrogen

What type of bond is a hydrogen bond?

Forms between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom

Van der Waals Interactions

Attractions between molecules close together due to uneven electron distribution within molecules.

Chemical Reactions

Involve the making and breaking of chemical bonds, with reactants transforming into products.

What is the process that converts carbon dioxide and water into glucose and oxygen?

Photosynthesis

What are the reactants in photosynthesis?

6 CO₂ + 6 H₂O

What are the products of photosynthesis?

C₆H₁₂O₆ + 6 O₂

How does water's unique properties support life?

Water exists in solid, liquid, and gas states, and interacts with other molecules.

In what states does water exist?

Water exists in solid, liquid, and gas states.

What are polar covalent bonds?

Electrons spend more time near one atom, creating a polar molecule with uneven charge distribution.

What enables hydrogen bonding in molecules?

Uneven charge distribution in polar molecules created by polar covalent bonds.

Cohesion

Collective hydrogen bonds holding water molecules together, aiding in water transport in plants.

Adhesion

Attraction between different substances, like water and plant cell walls, facilitating water movement in plants.

Surface Tension

Measure of a liquid's surface strength, with water's high value due to hydrogen bonding.

Moderation of Temperature

Water's ability to absorb and release heat slowly due to high specific heat, aiding temperature regulation.

Kinetic Energy

Energy of motion, with thermal energy associated with random atomic or molecular motion.

What is Specific Heat?

Amount of heat needed to change the temperature of a substance

What is the specific heat of water?

1 cal/(g · ºC)

Heat of Vaporization

Heat required for liquid to gas conversion, causing cooling, crucial for temperature stability.

Floating of Ice

Ice's less dense structure due to ordered hydrogen bonds, allowing it to float on liquid water.

Solution

Homogeneous mixture of solvent and solute, with water commonly the solvent in aqueous solutions.

Hydrophilic Substances

Substances with an affinity for water.

Hydrophobic Substances

Substances lacking an affinity for water, like oil due to nonpolar bonds.

Acidic and Basic Conditions

Shifts in H+ ions between water molecules, defining acids (increase H+) and bases (reduce H+).

Dynamic Equilibrium

State where water molecules dissociate and reform at the same rate.

Acids and Bases

Acids increase H+ concentration, bases reduce it, with strong ones fully dissociating.

What does the pH scale measure?

Acidity/basicity

What range of values on the pH scale is considered acidic?

Below 7

What range of values on the pH scale is considered basic?

Above 7

In which range of values on the pH scale are biological fluids commonly found?

6 to 8

Buffers

Substances maintaining H+ and OH- concentrations stable in solutions.

Carbon: The Backbone of Life

Carbon compounds form essential molecules in living matter.

Organic Chemistry

Study of carbon-containing compounds.