Biology Final Review: Key Concepts and Processes

Science

a pathway by which we can come to discover and better understand our world

Biology

the study of living things

Skepticism

Always evaluate the claims that people and companies make before accepting them as truth

Open-mindedness

Be willing to accept new discoveries as truth and change old ideas as new knowledge is uncovered

Biological Literacy

the ability to use the process of scientific inquiry to think creatively about real-world issues that have a biological component, communicate these thoughts to others, and integrate these ideas into your decision making

Scientific Method

a highly flexible process that can be used to explore a wide variety of thoughts, events, or phenomena

Observation

a key element of scientific thinking

Hypothesis

a proposed explanation for an observation that can generate a testable prediction, which can be proven or disproven using a critical experiment

Theory

an explanation for an observation that is exceptionally well supported by empirical data

Treatment

any experimental condition applied to the research subjects

Experimental Group

a group of subjects exposed to the experimental treatment

Control Group

a group of subjects who are meant to think they are the experimental group, but they do not receive the true treatment

Independent Variable

the variable the scientist manipulates or varies in an experimental study to explore its effects

Dependent Variable

the effect of the manipulations made by the scientist to the independent variable

Controlled Variables

aspects of the experiment (quantities, materials, environment, etc.) that the scientist keeps constant

Placebo Effect

the phenomenon that test subjects respond positively to ANY treatment

Blind Experimental Design

when the experimental subjects don't know whether or not they are receiving treatment or placebo

Double Blind Design

when neither the subjects nor the scientist know which treatment each group is getting

Randomization

when the subjects are randomly assigned into experimental and control groups

Bias

a disproportionate weight in favor of or against an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair

Pseudoscience

when individuals make scientific sounding claims that are not supported by trustworthy, methodical scientific studies

Anecdotal Observations

when individuals conclude that there is or is not a link between two things based on just one or two observations

Limitations of Science

Scientific thinking relies on measuring phenomena in some way. It can tell us what 'is' and not what 'ought to be'

Characteristics of Life

Cells, Energy, Response to stimuli, Growth and development, Reproduction, Evolution

Natural Selection

the process by which individuals that are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do

Steps of Darwin's Theory

Darwin's theory predicts that over time, the number of individuals that carry advantageous traits will increase in a population

Overproduction

Every population is capable of producing more offspring than can possibly survive

Variation

Variation in the form of inherited traits exists within every population.

Selection

Having a particular trait can make individuals more or less likely to survive and have successful offspring.

Adaptation

An adaptation is an inherited trait that is present in a population because the trait helps individuals survive and reproduce in a given environment.

Darwin's theory

Darwin's theory explains evolution as a gradual process of adaptation.

Fossil Record

You can infer past events by looking at fossils, traces of organisms that lived in the past.

Biogeography

Biogeography - the study of the locations of organisms around the world.

Convergent evolution

Convergent evolution: when organisms that aren't closely related evolve similar features or behaviours, often as solutions to the same problems.

Divergent evolution

Divergent evolution: when organisms that share a common ancestor evolve to have distinct features due to different environmental challenges.

Embryology

The study of embryonic development of species to look for similar patterns and structures.

Anatomy

The bodily structure, or anatomy, of different species can be compared to observe the results of evolution.

Homologous structures

Homologous structures: characteristics that are similar in two or more species and that have been inherited from a common ancestor of those species.

DNA Sequences

A comparison of DNA sequences shows that some species are more genetically similar than others.

Species

A species is a group of organisms with similar characteristics who can breed with one another to produce fertile offspring.

Reproductive isolation

Different species cannot interbreed to produce fertile offspring due to barriers called mechanisms of reproductive isolation.

Prezygotic barriers

A prezygotic barrier is one that prevents individuals from different species from engaging in the act of successful mating.

Postzygotic barriers

A postzygotic barrier is one that prevents a hybrid offspring from developing into a fertile adult.

Habitat isolation

A type of prezygotic barrier where species are separated by different habitats.

Temporal isolation

A type of prezygotic barrier where species breed at different times.

Behavioral isolation

A type of prezygotic barrier where species have different mating behaviors.

Gametic isolation

A type of prezygotic barrier where gametes of different species are incompatible.

Mechanical isolation

A type of prezygotic barrier where physical differences prevent successful mating.

Speciation

The formation of a new species.

Allopatric Speciation

Speciation that occurs due to geographic separation of populations.

Geographic barrier

A physical separation such as a mountain range or lava flow.

Genetic divergence

The gradual accumulation of differences in the genetic makeup of isolated populations.

Sympatric Speciation

Speciation that occurs within a population in the same location.

Polyploidy

Having more than two full sets of chromosomes, often leading to speciation.

Cell

The basic unit of all life.

Cell Theory

The theory that all organisms are composed of cells, cells are the basic units of structure and function, and cells come only from pre-existing cells.

Robert Brown

A scientist who contributed to the understanding that all life is made of cells.

Matthias Schleiden

A scientist who helped determine that plants are made of cells.

Theodor Schwann

A scientist who helped determine that animals are made of cells.

Rudolf Virchow

A scientist who showed that every cell comes from pre-existing cells.

Cell Size

Cells range in size from 1 millimeter (mm) to 1 micrometer (μm) in diameter.

Microscopes

Tools that help us view cells and their structures due to their small size.

Surface-Area-to-Volume Ratio

The relationship between the surface area of a cell's membrane and the volume of its cytoplasm.

Prokaryotic Cells

Cells that lack a membrane-bound nucleus.

Bacteria

Prokaryotic organisms that can cause diseases and are important as decomposers.

Archaea

Prokaryotic organisms that live in extreme habitats.

Eukaryotic Cells

Cells distinguished by the presence of a nucleus and internal membrane-bound organelles.

Endosymbiotic Theory

The proposal that eukaryotic organelles resulted from prokaryotic organisms being engulfed by larger cells.

Cyanobacteria

Single-celled organisms capable of photosynthesis.

Mitochondria

Organelles similar to bacteria in size and structure, surrounded by a double membrane, containing their own DNA.

Chloroplasts

Organelles that may have originated from engulfed cyanobacteria.

Rough Endoplasmic Reticulum (Rough ER)

A region of the endoplasmic reticulum that contains ribosomes and produces proteins.

Smooth Endoplasmic Reticulum (Smooth ER)

A region of the endoplasmic reticulum that does not have ribosomes, produces lipids, and helps detoxify the cell.

Golgi Apparatus

A stack of curved and flattened vesicles that modifies, sorts, and packages proteins and lipids.

Lysosomes

Membrane-bound vesicles produced by the Golgi apparatus that contain enzymes for breaking down substances.

Endomembrane System

A system that includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, and vesicles, compartmentalizing the cell.

Vesicles

Small membrane-bound sacs that transport materials within the cell.

Nucleus

The membrane-bound organelle that contains the cell's genetic material.

Organelles

Specialized structures within a cell that perform distinct functions.

Liver Cells

Specialized cells that have more smooth endoplasmic reticulum for detoxifying drugs.

Nerve Cells

Specialized cells that have more plasma membrane for carrying electrical impulses.

Transport Vesicles

Vesicles that carry substances from the endoplasmic reticulum to the Golgi apparatus.

Cis Face of Golgi Apparatus

The inner face of the Golgi apparatus directed towards the endoplasmic reticulum.

Trans Face of Golgi Apparatus

The outer face of the Golgi apparatus directed towards the plasma membrane.

Carbohydrate Chains

Molecules added to proteins in the Golgi apparatus that determine the proteins' final destination.

Low pH

The acidic environment within lysosomes that activates enzymes for digestion.

White Blood Cells

Cells of the immune system that contain many lysosomes to destroy foreign pathogens.

Membrane-bound Vesicles

Vesicles that are enclosed by a lipid bilayer, allowing them to fuse with other membranes.

Secretory vesicles

Carry products to the membrane where exocytosis produces secretions.

Cell Wall

A thick, rigid mesh of fibers that surrounds the outside of the plasma membrane.

Cell Wall in plant cells

Made out of cellulose.

Cell Wall in bacterial cells

Made out of peptidoglycan.

Cell Wall in fungi

Made out of chitin.

Function of the Cell Wall

Provides structural support and protection for the cell; keeps interior components intact.

Importance of the Cell Wall

Helps give shape and prevent over-expansion; first line of defense against environmental threats.

Cell Wall in bacteria

Essential for survival as it keeps the contents of the cell intact.

Antibiotics

Target the bacterial cell wall and cause lysis, leading to the expulsion of cellular contents and cell death.

Cytoplasm

A semifluid material that fills in the space within the cell membrane.

Function of the Cytoplasm

Gives shape to the cell and provides a medium for chemical reactions and cell transport.

Importance of the Cytoplasm

Provides a location for chemical reactions; many reactions need to happen in a solution.