Biology First Exam Notes

Biology

Scientific study of organisms both living and dead

Common features

Shared characteristics among related organisms.

Prokaryotes

Single-celled organisms without a nucleus.

Examples of prokaryotes

Bacteria and Archaea

Eukaryotes

organisms made up of one or more cells that have a nucleus and membrane-bound organelles

All life as a common ___

Ancestor

Nucleic acids

DNA and RNA

Central dogma of molecular biology

DNA -> RNA -> Protein

Protein synthesis

Forming proteins based on information in DNA and carried out by RNA

Liposomes

Closed Lipid bilayer spheres that encapsulate ingredients, target their delivery to specific tissues of the skin, and control their release

Nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

Photosynthesis

Conversion of light energy from the sun into chemical energy.

Cyanobacteria

Bacteria that can carry out photosynthesis

Aerobic metabolism

Metabolism that can proceed only in the presence of oxygen.

Anaerobic Metabolism

The metabolism that takes place in the absence of oxygen; the principle product is lactic acid.

Most organisms today use which type of metabolism?

Aerobic metabolism

What led to formation of ozone layer?

Accumulating O2 led to formation of the ozone (O3) layer, which absorbs damaging UV radiation.

Where did organisms live before ozone layer was formed?

Bodies of water

Cellular differentation

Process that creates different types of specialized cells

Cell specialization allowed:

organisms to get larger and become more efficient

Levels of biological organization

atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, biosphere

Atoms

Building blocks of matter

Molecules

Groups of two or more atoms held together by chemical bonds

organelles

A tiny cell structure that carries out a specific function within the cell

cells

smallest living unit of life

tissues

Groups of cells with a common structure and function.

organs

Groups of tissues that work together to perform a specific function or related functions

organ systems

A group of organs that work together in performing vital body functions.

Population

A group of individuals that belong to the same species and live in the same area

Community

All the different populations that live together in an area

Ecosystem

A community of organisms and their abiotic environment

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.

work

movement; biochemical work; electrical work

How can energy be stored?

carbs & fat

Homeostasis

A tendency to maintain a balanced or constant internal state

Sensory mechanisms

the means by which internal or external stimuli are converted into neural signals

Characteristics of living organisms

cellular composition, metabolism, growth, excretion, responsiveness, movement, reproduction

genes

Chemical factors that determine traits

Genome

sum total of all the DNA molecules in an organism

Qualities of DNA

1. Double stranded

2. A, T, C, G

3. Deoxyribose

nucleotide sequences determines:

the amino acid sequences in proteins.

Mutations

a random error in gene replication that leads to a change (usually harmful)

Evolution

The gradual change in a species over time

Major unifying principle of biology:

evolution

Natural Selection

A natural process resulting in the evolution of organisms best adapted to the environment.

artificial selection

Breeding organisms with specific traits in order to produce offspring with desired traits.

Adaptations

Changes in physical structure, function, or behavior that allow an organism or species to survive and reproduce in a given environment.

Genomics

study of whole genomes, including genes and their functions

Binomial

distinct scientific name (genus and species)

Genus

group of species that share a recent common ancestor

Species

A group of similar organisms that can breed and produce fertile offspring.

phylogenetic tree

Diagram showing evolutionary relationships among species.

What are scientific investigations based on?

observation, experimentation, data analysis, and logic

Controlled Experiments

one variable is manipulated while others are held constant

Comparative experiments

compare data gathered from populations that differ in multiple ways

Model Systems

using one type of organism to understand others

Qualities of a hypothesis

testable and potential to be rejected

Phylogeny

Evolutionary history of a species

lineage

a series of ancestor and descendant populations

A lineage that divides into two:

node

When lineages split they form:

branches

Common ancestor of all organisms in phylogenetic tree:

root

Taxon

any group of species that we designate or name

Clade

a taxon that has all the descendants of a common ancestor

sister species

two species that are each other's closest relatives

sister clades

two clades that are each other's closest relatives

Homologous features

similar features that originated in a shared ancestor

ancestral trait

characteristic that existed in an ancestor

derived trait

a trait that differs from the ancestral trait

Synapomorphies

derived traits shared among a group; they are viewed as evidence of the common ancestry of the group

convergent evolution

the independent evolution of similar features in different lineages bird and bat wings

analogous traits

functionally similar structures that have independent origins

evolutionary reversal

the reversion of a derived character state to its ancestral state

Homoplasies

analogous structures that arose independently

ingroup

group of primary interest

Outgroup

closely related species/group known to be outside the group interest

parsimony principle

the preferred explanation of observed data is the simplest explanation

Morphology

study of form

Most widely used data for phylogenetic trees:

Molecular data

binomial nomenclature

Classification system in which each species is assigned a two-part scientific name

Kingdom

Animalia

Monophyletic

ALL descendants came from one common ancestor

A taxon is a:

clade

polyphyletic

a group that does not include its common ancestor (two or more common ancestors)

paraphyletic

pertaining to a grouping of species that consists of an ancestral species and some, but not all, of its descendants.

parts of cell theory:

1. Cells are the fundamental units of life.

2. All organisms are composed of cells.

3. All cells come from preexisting cells.

4. Modern cells evolved from a common

ancestor.

Why are cells small?

to maintain a high surface area to volume ratio

As cell volume increases, what else increases?

Chemical activity and waste removal

Cell/plasma membrane

phospholipid bilayer that protects and encloses the cell; controls transport; maintains homeostasis

Cytoplasm

everything in the cell except the nucleus

Cytosol

Fluid portion of cytoplasm

The cell membrane has a ____ ____ barrier

selectively permeable

Cells with no membrane bound organelles:

prokaryotes

Cells with membrane bound organelles

Eukaryotes

Features of prokaryotic cells

no nucleus, DNA freely floating in nucleoid, no membrane-bound organelles, cytoplasm, ribosomes

Peptidoglycan

A protein-carbohydrate compound that makes the cell walls of bacteria rigid

Bacteria that carry out photosynthesis have an:

internal membrane system that contains the molecules needed for photosynthesis

Cytoskeleton

system of protein filaments that maintain shape, moves the cell, and assists in cell division

Flagella

A long, whip-like filament that helps in cell motility.

Pili

short, hairlike protein structures on the surface of some bacteria