biology EXAM #1 pt. 1 Flashcards
Science :
- the investigation of rational concepts that can be evaluated
Hypothesis :
a proposed explanation for an observed phenomenon
Theory :
- a hypothesis that is consistent with all available evidence
Biology :
Is the scientific study of life by observations and experimentation.
The study of life:
Extends from the microscope scale of molecules and cells to the global scale of the entire living planet
Biologists ask questions such as:
How does a single cell develop into an organism?
How does the human mind work?
How do living things interact in communities?
Life is :
recognized by what living things do
There are five unifying themes:
-Organization
-Information
-Energy and matter
-Interactions
-Evolution
The hierarchy of life:
Extends through many levels of biological organization
Order of biggest unit of structure to smallest
- Biosphere
- Ecosystems
- Communities
- Populations
- Organisms
- Organs and Organ systems
- Tissues
- Cells
- Organelles
- Molecules
The cell :
– An organism’s basic unit of structure and function
-Is the lowest level of organization that can perform all activities required for life
Every cell is enclosed:
enclosed by a membrane that regulates passage of materials between the cell and its environment
All cells share certain characteristics:
- They are all enclosed by a membrane
- They all use DNA as genetic information
There are two main forms of cells:
Eukaryotic
Prokaryotic
Eukaryotic cells:
Are subdivided by internal membranes into various membrane-enclosed organelles
-nucleus (contains DNA)
Prokaryotic cells:
Lack the kinds of membrane-enclosed organelles found in eukaryotic cells
-DNA (no nucleus)
Cells contain chromosomes made partly:
of DNA, the substance of genes
Which program the cells’ production of proteins and transmit information from parents to offspring
Each chromosome has:
one long DNA molecule with hundreds or thousands of genes
Genes :
encode:
units of?
-encode information for building the molecules synthesized within the cell
-units of inheritance
DNA controls:
controls the development and maintenance of organisms
Genes control:
process-
protein production indirectly.
DNA is transcribed into RNA, which is then translated into a protein
Gene expression:
is the process of converting information from gene to cellular product
Interactions between components that make up living organisms are:
components:-organs, tissues, cells, and molecules
are: crucial to their smooth operation
Cells are able to cooordinate:
coordinate various chemical pathways through a mechanism called feedback
In feedback regulation:
the output, or product of a process, regulates that very process
The most common form of regulation in living organisms is:
negative feedback, in which the response reduces the initial stimulus
A less common form of regulation is:
positive feedback, in which an end product speeds up its own production
Feedback is:
a regulatory motif common to life at all levels
An organism’s genome :
is its entire set of genetic instructions
The human genome and those of many other organisms :
have been sequenced
Genomics:
is the study of sets of genes within and between species
Proteomics:
is the study of whole sets of proteins encoded by the genome (known as proteomes)
The genomics approach depends on:
-“High-throughput” technology, which yields enormous amounts of data
-Bioinformatics, which is the use of computational tools to process a large volume of data
-Interdisciplinary research teams
Each organism:
Both organism and environment:
-Interacts with its environment
-Are affected by the interactions between them
The dynamics of any ecosystem include two major processes:
-Cycling of nutrients: materials acquired by plants eventually return to the soil
-The flow of energy: from sunlight to producers to consumers
All activities of life require:
-organisms to perform work, which depends on an energy source (the sun, other organisms…)
The exchange of energy between an organism and its surroundings
Often involves:
the transformation of one form of energy to another
Energy flows__________ through an ecosystem usually entering :
-one direction
-as sunlight and exiting as heat
Interactions between the components of the system ensure:
-This holds true equally well for components of :
smooth integration of all the parts
-an ecosystem and the molecules in a cell
At the ecosystem level, each organism interacts continuously :
These interactions may be:
with other organisms
- beneficial or harmful to one or both of the organisms
Organisms also interact continuously with __________________, and the environment is affected by:
-the physical factors in their environment
-the organisms living there
Over the past 150 years,
humans have greatly increased the burning of fossil fuels and the release of carbon dioxide (CO2) into the atmosphere
___________________ is just one aspect of climate change
-_________________ patterns are also shifting
-____________________ are occurring more often
-The resulting global warming
-Wind and precipitation
-Extreme weather events such as storms and droughts
As habitats deteriorate,
plant and animal species shift their ranges to more suitable locations
Populations of many species are:
shrinking in size or even disappearing
Evolution is the one idea:
that makes logical sense of everything we know about living organisms
The scientific explanation for both the unity and diversity of organisms is:
the concept that living organisms are modified descendants of common ancestors
Approximately #______ species have been identified and named to date, and __________ more are identified each year
-1.8 million
-thousands
Estimates of the total number of species that actually exist range from
10 million to over 100 million
Taxonomy:
Is the branch of biology that names and classifies species according to a system of broader and broader groups
Classifying Life:
- Species
- Genus
- Family
- Order
- Class
- Phylum
- Kingdom
- Domain