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120 terms

Biology exam notecards

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Biology
The science of life.
Cells
Basic units of structure and fuction in all living things
Reproduction
production of offspring
Homeostasis and example of it
regulation of an organism's internal conditions to maintain life
Adaptation
any inherited characteristic that results from changes to a species over time
Science
body of knowledge based on the study of nature
Hypothesis
Testable explanation of a situation
Matter
Anything that has mass and takes up space
Chemistry
study of matter
Atoms
building bloks of matter
Element
Pure substance that cannot be broken down into other substances by physical or chemical means
Compound
PUre substance formed when two or more different elemnts combine
Chemical bonds
force that holds substances together
Molecule
Compound in which the atoms are held together by ovalent bonds
Enzymes
special proteins that are biological catalysts that speed up the rate of chemical reactions in biological process
Carbohydrate
They are sources of energy composed of carbon, hydrogen, and oxygen; that include simple sugars
Lipid
They are made up of carbon and hydrogen and they store energy and make up fats, oils, and waxes
Protein
made up of amino acids
Nucleic Acids
macromolecules that store and transmit genetic information
ATP
storehouse of chemical energy that can be used by cells in a variety of reactions
Plasma membrane
boundary that controls what enters and leaves the cell
Metabolism
All of the chemical reactions within a cell
Organelles
Specialized structures that carry out specific cell functions
Where genetic info in a cell is located
Nucleus
Cytoplasm
The environment inside the plasma membrane; semi-fluid material
Ribosomes
They are made up of RNA and protein, are produced in the nucleolus and some are free and others are attached to the endoplasmic reticulum
Endoplasmic Reticulum
membrane system of folded sacs and interconnected channels that serves as the site for proteins and lipid synthesis
Golgi Apparatus
Organelle that is a Flattened stack of membranes that modifies, sorts and packages proteins into sacs which then fuses with the plasma membrane to release the proteins into the environment outside the cell
Vacuole
organelle used for storage
Lysosome
digests old organelles and food
Centrioles
group of microtubes that function during cell division in animal cells
Chloroplasts
Capture light energy and converts it to chemical energy by photosynthesis
Mitochondria
Is the powerhouse of the cell that converts sugars into energy for the cell and it has 2 membranes
Cell Walls
Only in plants and they contain cellulose and they protect and support the cell
Cilia
They are short hair-like projections used for movement
Flagella
Longer, less numerous and move a cell with a whip-like motion
Diffusion
Net movement of particles from and area where there are fewer paricles than an area where there are many particles of the substance to an area where they are fewer paticles of the substance
Facilitated Diffusion
transport proteins move ions and small molecules across the membrane-Also doesn't require energy and is also called passive transport
Osmosis
diffusion of water across a selectivley permeable membrane
Active Transport
Movement of substances across the plasma membrane against a concentration gradient (low to high) and requires energy
Autotrophs
They are organisms that make their own food
Heterotrophs
organisms that obtain energy from the foods they consume
Photosynthesis
anabolic pathway in which light energy from the sin is converted into chemical energy for use by the cells
Cellular Respiration
catabolic pathway in which organic molecules are broken down to release energy for use by the cell
Cell Cycle
The way cells reproduce by a cycle of growing and dividing
Three main stages of cell cycle
1. Interphase 2. Mitosis 3. Cytokinesis
Interphase
Stage of the cell cycle during which the cells grows and makes copies of its DNA in preparation for the next stage
Mitosis
Stage during which the cell's nucleus and nuclear material divide.
Cytokinesis
Is the method by which a cell's cytoplasm divides creating 2 new cells
Chromosomes
Structures that contain the genetic material that is passed from generation to the next.
Prophase
It is the longest phase where the nucleus and nucleolus seem to disappear. The spindle fibers form and attach to sister chromatids and centrioles migrate toward opposite poles
Metaphase
where sister chromatids are pulled along the spindle apparatus toward the center of the cell and line up in the middle
Anaphase
chromatids are pulled apart as the spindle fibers shorten and chromosomes move toward the opposite poles of the cell
Telophase
Chromosomes arrive at the poles and begin to relax; two nuclear membranes begin to form and spindle apparatus disappears
End Result of Mitosis
2 identical cells
Carcinogens
substances and agents that are known to cause cancer
Stem Cells
Cells that are unspecialized that can develop into specialized cells when under the right conditions
Genes
DNA on chromosomal segments that control the production of proteins
Number of chromosomes in human body
46
Gametes
Sex cells
Number of chromosomes in human sex cells
23
Meiosis
Where gametes are formed during a type of cell division that reduces the number of chromosomes
Prophase I
Replicated chromosomes become visible and consist of 2 sister chromatids. The chromosomes are beginning to form pairs and crossing over may occur
End result of meiosis
4 unidentical cells
Genetics
The science of heredity
Allele
An alternative form of a single gene passed from generation to generation
Which allele is masked over by which
Recessive is masked by the dominant
Homozygous
An organism with 2 of the same alleles for a particular trait
Heterozygous
An organism with 2 different alleles for a trait
Genotype
an organism's allele pairs
Phenotypes
Obervable outward expression of an organism's allele pair
Alkaptonuria
Disorder characterized by black urine. Appears at birth and affects bones and joints and was studied by Dr. Garrod
Cystic Fibrosis
disorder that affects the mucus-producing clands, digestive enzymes and sweat glands.
Albinism
disorder that is cause by the altered genes resulting the absence of the skin pigment melanin in hair and eyes
How Tay-Sachs disease is diagnosed and what does it do to the body
identified as a cherry-red spot on the back of the eye . It is caused by the absence of the enzymes responsible for breaking down fatty acids called gangliosides
Huntington's disease
genetic disorder that affects the nervous system appears in individuals between 30 and 50
Pedigree
diagram that traces the inheritance of a particular train through several generations
Incomplete dominance and give an example
the heterozygous phenotype is an intermediate between the two homozygous phenotypes Ex: snapdragons
Codominance and give an example
both alleles are expressed in the heterozygous condition for example sickle-cell disease
Sex chromosomes for males/females
XX-female XY-male
Sex-linked traits
traits controlled by genes located on the X chromosome
Barr body
inactive X chromosome
Karyotype
pairs of homologous chromosomes that are arranged in decreasing size to produce a micrograph or picture
Nondisjunction
the sister chromatids fail to separate properly
Parts of nucleotide
phophate, 5 carbon sugar, nitrogenous bases
Nitrogenous bases in DNA
adenine, guanine, thymine, cytosine
What is different about RNA
adenine, guanine, uracil, cytosine
Who built first model of DNA
Watson and Crick
Outside strand of DNA
Phosphate and sugar
Replication
Parental strands of DNA separate serve as templates and produce DNA molecules that have one strand of parental DNA and one new strand of DNA
Bases in DNA held together by
hydrogen bonds
Code for proteins comes from.......
DNA
The mechanism for reading to expressing genes is from
DNA to RNA to protein
3 Types of RNA
rRNA, mRNA, tRNA
In DNA, how the bases pair up
Adenine matches with Thymine Cytosine matches with Guanine
In RNA different in pairings
Adenine matches with Uracil
mRNA
Messenger that carries genetic information from DNA in the nucleus to direct protein synthesis in the cytoplasm
tRNA
transports amino acids to the ribosome
Transcription
synthesis of mRNA from DNA
Codons
3 bases in DNA read together
Translation
mRNA moves to the ribosome and the code is read and translated to make a protein
Mutation
permanent change in a cell's DNA
Mutagens
substances that cause mutations
Who discovered the base pairings in DNA
Chargaff
bio-
life
cyto-
cell
troph
nourish
chlor-
green
inter-
between
hetero-
different
homo-
same
di-
two
gam-
united, joined, sexual
tri-
three
zyg-
yolk, union
eu-
good, well, true
uni-
one
pro-
before, primary
aer-
air, oxygen
exo-
out of, outer