Transcript 1 Scientific Method - Biology

#1 Scientific Method
• Steps that scientists use to gather
information and answer questions.
• Problem/Question, Hypothesis,
Experiment, Conclusion, Theory
• Data-quantitative (numbers) or qualitative
(descriptions)
#2 Hypothesis
• Explanation for a question or a problem
that can be formally tested.
• Sometimes an “If…then” statement.
• Educated guess.
#3 Bias
• Personal and unscientific judgment that
may alter the results of an experiment.
• Opinion or belief
#4 Independent Variable
• In an experiment, the condition that is
changed because it affects the outcome of
the experiment.
• Manipulated variable.
#5 Dependent Variable
• In an experiment, the condition that results
from changes in the independent variable.
• Measured variable.
#6 Metric System
• Mass- gram-triple beam balance
• Length- meter- meter stick
• Volume- liter- graduated cylinder
#7 Heterotroph
• An organism that must consume its food. It
cannot produce its own.
• Consumer.
• Herbivore, carnivore or omnivore.
#8 Autotroph
• An organism that can produce its own
food.
• Uses photosynthesis or chemosynthesis.
• Producer.
#9 Biology
• Study of living things.
• Animals, plants, bacteria
#10 Biotic
• Living part of an ecosystem.
• Ex. Plants, animals, fungi, bacteria
#11 Abiotic
• Nonliving part of an ecosystem.
• Air, water, soil
#12 Homeostasis
• Maintaining a stable internal environment.
• Including body temperature and amount of
water and nutrients.
#13 Metabolism
• All of the chemical reactions that take
place in an organism.
#14 Characteristics of living things
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Made of cells
Reproduce
Have DNA
Grow/Develop
Obtain and use energy
Respond to environment (Homeostasis)
Adapt
#15 Atoms
• Made of protons (+), neutrons(0), and
electrons (-).
• Protons and neutrons in nucleus,
electrons are in electron cloud.
• Can form bonds to make molecules and
compounds.
#16 Bonds
• Covalent Bonds- share valence electrons
• Ionic bonds- formed by oppositely
charged ions; + & • Hydrogen bonds- weak covalent bonds
between hydrogen atoms; found in water
and DNA
#16 Ions
• An atom that has a positive or negative
charge
• When atoms lose electrons they form a
positive ion
• When atoms gain electrons they form a
negative ion
#17 Adhesion
• An attraction between molecules of
different substances.
• Helps water stick to surfaces.
• Capillary action is when water moves
against the force of gravity. Like from the
roots to the top of a tree.
#18 Cohesion
• An attraction between molecules of the
same substance.
• Helps water stick to itself.
• This is why water beads on a smooth
surface.
#19 Acid
• A compound that forms H+ ions in water.
• Below 7 on the pH scale.
#20 Base
• A compound that produces OH- ions in
water.
• Above 7 on the pH scale.
#21 Carbohydrate
• Contains carbon, hydrogen and oxygen.
• Main source of energy from food.
• Sugars and starches
#22 Protein
• Contains carbon, hydrogen, oxygen and
nitrogen (sometimes sulfur).
• Made of amino acids.
• Used for structure, organic catalysts and
gene expression.
#23 Enzyme
• A protein.
• Biological catalyst- speeds up chemical
reactions in the body.
#24 Nucleic Acid
• Store and transmit genetic information.
• DNA and RNA
• Made of nucleotides.
#25 Lipid
• Used for long-term energy storage,
protective coatings and insulation.
• Made of a glycerol and three fatty acids.
• Fats, oils and waxes.
#26 Monomer
• Subunit or building block of a larger
molecule.
• Many monomers bonded together make a
polymer.
• Polymers are large molecules.
#27 Monosaccharide
• Monomer of carbohydrates.
• Simple sugar.
• Glucose, fructose, galactose
#28 Amino acid
• Monomer of proteins.
• 20 different kinds
• The order of amino acids that goes in a
protein are encoded in DNA.
• Has an amino group (-NH2) and a
carboxyl group (-COOH).
#29 Nucleotide
• Monomer of nucleic acids.
• Made of a phosphate group, 5-carbon
sugar, and a nitrogen base.
# 30 Cell Theory
• All living things are made of cells
• The cell is the basic unit of life
• All cells come from preexisting cells
#31 Prokaryote
• Cells that do not contain a nucleus or
membrane-bound organelles.
• DNA floats in cytoplasm.
• May contain a cell wall.
• Ex. Bacteria
#32 Eukaryote
• Cells that contain a nucleus and membranebound organelles.
• Animal and plant cells.
#33 Cell Membrane
• Outer boundary of the cell, which regulates what
enters and exits the cell.
• Selectively permeable.
• Made of phospholipids and proteins.
• “Fluid Mosaic”
#34 Ribosome
• Site of protein synthesis (translation).
• Spherical body found floating in the
cytoplasm or attached to endoplasmic
reticulum.
• Made of rRNA and proteins.
#35 Cytoplasm/Cytosol
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Fluid matrix inside the cell
Many chemical reactions take place here.
Organelles float in the cytoplasm.
Made mostly of water
#36 Nucleus
• Controls the activities of the cell
• Contains the hereditary information of the
cell (DNA)
• Surrounded by the nuclear envelope
• Contains the nucleolus which makes
ribosomes
#37 Endoplasmic Reticulum
• Set of tubular
passageways involved
with the transport of
molecules in the cell.
• Smooth ER- no
ribosomes; transports
lipids
• Rough ER- ribosomes
attached; transports
proteins
#38 Mitochondria
• The organelle that
releases energy from
stored food
molecules.
• Site of cellular
respiration.
• Highly folded
membranes to
increase surface
area.
#39 Golgi Apparatus
• Stack of flattened membranes that processes
and packages proteins to be secreted out of the
cell
#40 Chloroplast
• Site of photosynthesis in the plant cell.
• Houses chlorophyll.
• Made of stacks of thylakoids called grana
and inner space called stroma.
#41 Lysosome
• Small organelles filled with enzymes
• Breaks down particles for the cell to use
#42 Cytoskeleton
• Network of protein filaments that help the
cell maintain its shape
• Made of microtubules (hollow) and
microfilaments (rods)
#43 Vacuole
• Saclike structures used by the cell to store
water, salts, proteins, and carbohydrates
• Large central vacuole in the plant cells
• Small or not present in animal cells
#44 Centriole
• Only in animal cells
• Involved in cell division
• Make the spindle that pulls chromosomes
apart
#45 Cilia & Flagella
• Used in cell movement
• Cilia- hairlike projection, numerous
• Flagella- taillike structures, 1-3
#46 Vesicle
• Transport containers for the cell.
• Made from the Golgi Apparatus and the
cell membrane.
#47 Passive Transport
• Movement of particles across cell
membranes by moving with the
concentration gradient.
• Diffusion or osmosis.
• Uses no energy.
#48 Diffusion
• Net, random movement of particles from
an area of higher concentration to an area
of lower concentration.
• Eventually results in even distribution.
#49 Osmosis
• Diffusion of water across a selectively
permeable membrane.
• Depends on the concentration of solutes
on either side of the membrane.
#50 Osmotic Solutions
• Hypotonic solutions- Solutions that have a
lower concentration of solute than the solution
inside the cell. This causes water to move into
the cell and the cell will swell.
• Hypertonic solutions- Solutions that have a
higher concentration of solute than the solution
inside the cell. This causes water to move out of
the cell and the cell will shrink.
• Isotonic solutions- The solutions inside and
outside the cell have the same concentration of
solute. The cell does not change shape.
#51 Active Transport
• Process by which cells transport materials
across the cell membrane against a
concentration gradient.
• Uses energy.
#52 Endocytosis
• Process of taking material into the cell by
means of vesicles.
• Pinocytosis- “cell drinking”
• Phagocytosis- “cell eating”
#53 Exocytosis
• The removal of large particles from the
cell.
• Vesicles fuse with the cell membrane and
force contents out of the cell.
#54 ATP
• Adenosine
triphosphate
• Stored cellular
energy
• Made from
adding a
phosphate to
ADP.
#55 Photosynthesis
• Process by which plants use light energy to
convert water and carbon dioxide into glucose
and oxygen.
• Happens in the chloroplast.
6CO2 + 6H2O + light  C6H12O6 + 6O2
Carbon+water+sunlightGlucose+oxygen
Dioxide
#56 Cellular Respiration
• Breaking down of glucose into usable
energy (ATP).
• Aerobic
• Happens in mitochondria.
C6H12O6 + 6O2  6H2O + 6CO2 + 36 ATP
Glucose +Oxygen Water + Carbon + Energy
dioxide
#57 Aerobic
• Reaction that requires oxygen.
• Cellular respiration
#58 Anaerobic
• Reaction that does not require oxygen.
• Fermentation
#59 Fermentation
• Anaerobic breakdown of organic
substances.
• Alcoholic- gives of alcohol & carbon
dioxide
• Lactic acid- gives off lactic acid.
#60 Cell Cycle
A. G1
B. S
M phase
C. G2
D. Metaphase
#61 Chromosome
• Compact form of DNA
and protein in the
nucleus of a cell
about to divide.
• Come in homologous
pairs in diploid cells.
Centromere
Sister Chromatids
#62 Chromatin
• Genetic material that is found in the
nucleus of a nondividing cell.
• Unwound, stringy form of DNA.
#63 Mitosis
• Cell division in which two daughter cells
are produced, each containing a complete
set of chromosomes.
• Done by somatic cells.
• Diploid cell division.
• Prophase, metaphase, anaphase,
telophase.
#64 Cytokinesis
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Division of the cytoplasm.
Happens at the end of cell division.
Animal cells- pinch inwards; cleavage
Plant cells- form cell plate down center of
cell
#65 Gamete
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Sex cells
Female- egg cell; Male- sperm
Haploid
Made during meiosis
#66 Haploid
• Cell with one of each type of chromosome.
• n
• Sex cells
#67 Diploid
• Cell with two of each type of chromosome.
• 2n
• Somatic cells.
#68 Meiosis
• Type of cell division in which a body cell
produces four sex cells (gametes).
• Each gamete contains half the number of
chromosomes as the original cell.
• All four cells produced are genetically
different.
#69 Crossing Over
• When chromosomes pair up and
exchange parts of their chromatids.
• This creates genetic variations.
• Happens during prophase I.