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What do scientists do to verify results?
Scientists verify their conclusions by conducting experiments & studies many times. They also check to see if other scientists have found the similar results.
Reasons for studying science?
an understanding of science can help you take better care of your health, be a wiser consumer, & become a better informed citizen. Also medicine, health care, learning thru education, & technology
what is the metric system?
the International System of Units (SI) the official name for the metric system. It's used by all scientists because scientists need to share a common measurement system. It is also preferred because it is scaled by multiples of 10. its a decimal system
ind. vs dep. variable
the single factor that scientists change in an experiment is called the independent variable
Factors that may change in response to the independent variable are called dependent variables.
Scientists must use caution to avoid dangers such as chemical burns, exposure to radiation & infectious disease, animal bites, or poisonous plants
what is homeostasis
the maintenance of stable internal conditions in spite of changes in the external environment.
Ethics in science?
- because scientific experimentation & discovery can have serious ethical implications, scientific investigations require ethical behavior. Science has to take ethical issues into consideration before, during & after experimentation.
- Safety of the subjects
- Validity of Experiment
what is a hypothesis
It's a possible explanation that can be tested by observation or experimentation. they are not guesses.
what is an experiment
an experiment is a procedure that is carried out under controlled conditions to test a hypothesis. Scientists conduct controlled experiments or perform studies in order to test a hypothesis,
what is a theory ?
When related hypotheses are well supported & explain a great amount of data, these hypothesis may be put together to form a theory.
what is biology?
it's the study of life. branches include: biochemistry, ecology, cell biology, genetics, evolutionary theory, microbiology, botany, zoology, & physiology.
- help magnify organisms.
- 2 common kinds of microscopes are light & electron microscopes.
- in light microscopes light passes through one or more lenses to produce an enlarged image of an object.
- An electron microscope forms an image of an object by using a beam of electrons to magnify extremely small objects.
what is a pathogen?
an agent that causes disease.
how does science help people live longer?
- as scientists learn more about the nature of disease, our ability to prevent & treat diseases has improved.
- new discoveries in genetics
- As our understanding of medicine, bio, & science in general increases, humans will live longer & happier lives.
- assistive techn. bionic limbs & computer interfaces.
- battlefield medicine- remote surgery & battlefield bandage device
what is Bt corn?
corn that has been altered to contain a gene from a naturally occurring soil bacterium called Bacillus thuringiensis. this raised crop yields and lower the amount of pesticides. genetic engineering
what is a device?
a piece of equipment made for a specific use
tools such as satellite tagging, geographic info sys (GIS), & genetics are used to study & protect the environment.
uses satellite data.
its a powerful tool in environmental research because it allows biologists to compare different kinds of data. also allows researchers to have access to data from many different studies so that they can work together.
has nothing to do w/ a person's actual finger but rather is a unique pattern of DNA that represents the total of a person's genetic material. Evidence such as hair or skin can be identified using DNA fingerprinting
where are electrons found?
surrounding the nucleus in an electron cloud
matter is composed of?
- they are molecules made of sugars.
- monosaccharide single sugar~ glucose
- 2 sugars linked together sucrose (table sugar) & lactose
- many sugars linked a polysaccharide ~ starch
- mono & di are simple carbs poly is complex.
- cells use carbs for sources of energy, structural materials, & cellular identification.
- Energy supply ~ are a major source of energy for many organisms including humans.
- structural support~ chitin & cellulose are 2 complex carbs that provide support
- cell recognition~ carbs on the outside of invading cells allow the body to recognize them as not being part of the body do that they can be destroyed
what is an atom?
- the smallest unit if matter that cannot be broken down by chemical means. All matter is made up of atoms . positively charged core & neg charged region surrounds.
- atoms have no charge
- made of protons, neutrons, & electrons.
what is the most basic unit of most biomolecules?
contains atoms of carbon. Carbon atoms have four valence electrons, so they can form covalent bonds w/ as many as four other atoms.
law of conservation of energy
every change in matter requires a change in energy. Energy may change from one form to another, but the total amount of energy does not change.
what is succession
the replacement of one community by another at a single place over a period of time.
factors that determine a biome?
a specific kind of climate & certain kinds of plant & animal communities.
- aquatic ecosystems are organized into freshwater ecosystems, wetlands, estuaries, and marine ecosystems.
- freshwater ecosystems: located in bodies of fresh water such as lakes, ponds, & rivers. These ecosystems have a variety of plants, fish, arthropods, mollusks, & other invertebrates.
Wetlands: provide a link between the land and fully aquatic habitats. water-loving plants dominate. Supports many birds, fishes, & plants. Wetland are important because they moderate flooding & clean the water that flows thru them.
- estuary: an area where fresh water from a river mixes w/ salt water from an ocean. Productive ecosystems because they constantly receive fresh nutrients from the river & the oceans
- marine ecosystems: found in the salty waters of the oceans.
what are decomposers?
fungi & bacteria, organisms that break down the remains of animals.
what is a community?
a group of various species that live in the same place & interact w/ one another.
what is a biome?
a large region characterized by a specific kind of climate & certain kinds of plant & animal communities.
what is a bayou
- an example of a wetland
- the coral reef is an example of a marine ecosystem
ideal cell size and shape?
- cells w/ a greater surface area to volume ratio are more efficient.
- broad & flat
what is the cell theory?
- all living things are made up of one or more cells
- cells are the basic units of structure & function in organisms
- all cells arise from existing cells
what the central vacuole
- contained in many plant cells.
- stores waters, ions, nutrients, wastes, pigments, & toxins
- when filled with water plant is rigid
- when depleted of water plants wilts
what is chloroplast?
an organelle that uses light energy to make sugar form carbon dioxide & water. Each is surrounded by a pair of membranes. Inside the inner membrane are many stacks of flattened sacs, where ATP is produced.
what is a ribosome?
a cellular structure on which proteins are made.
what is an organelle?
a structure that carries out specific activities inside the cell.
prokaryotic vs eukaryotic
prokaryotic: simple in organization. genetic material is a single loop of DNA. Ribosomes & enzymes share the cytoplasm w/ DNA. have a cell wall which surrounds the membrane & provides structure & support. some are surrounded by a capsule a structure that enables it to cling to surfaces. up to 3.5 billions years or more. make up a large & diverse group of cells
- eukaryotic cells: some live as a single cell. Others are multicellular organisms, all multicellular organisms are made up of eukaryotic cells.
- Because of their complex org. they can carryout more specialized function them prokaryotes can.
- 1.5 billion years ago.
- contains compartments separated by membranes.
- cells DNA is housed in the nucleus.
- membrane organelles
what is diffusion?
substance move from an area of higher concentration to an area of lower concentration.
what is osmosis?
- a type of passive transport that is very important to keeping cells functional. Water can diffuse across a selectively permeable membrane during this process.
- it allows cells to maintain water balance as their environment changes.
- occurs as free water molecules move down their concentration gradient into the solution that has the lower concentration of free water molecules.
requires energy to move substance up the concentration gradient.
produces signals often a molecule.
- organisms that are able to perform photosynthesis.
- make organic compounds that serve as food for them & for almost all of the other organisms on earth.
use sunlight to make organic compounds from carbon dioxide & water.
- is cell currency
- adenosine tri phosphate
- minus one phosphate group is ADP
- made of 3 phosphate groups
- all neg charged so unstable
by products of photosynthesis
aerobic vs anaerobic
uses oxygen vs does not use oxygen
what is cellular respiration
cells make the carbon in glucose into stable carbon dioxide molecules & produce energy.
- a green pigment in chloroplasts that absorbs light energy to start photosynthesis. absorbs mostly blue, & red & reflects green & yellow. making plants appear green
- plants have to types of chlorophyll
- chlorophyll a & chlorophyll b
fermentation and glycolysis
- recycles NAD+ that is needed to continue making ATP through glycolysis.
- Fermentation enables glycolysis to continue supplying a cell w/ ATP in anaerobic conditions.