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LS Semester 1 Test

Cards to study for 7th grade life science semester 1 exam.

A ________________________ is a representation of an object or a system. model
The study of living things is ______________________________________. life science
Organisms maintain internal stability despite threats by external stimuli through ___________________. homeostasis
Molecules that are sometimes called the blueprints of life are __________________________________. nucleic acids
All of the chemical activities that an organism’s cells perform are called __________________________. metabolism
A living thing that makes its own food. producer
A series of steps followed by scientists to solve problems. scientific method
A living thing that breaks down the nutrients of dead organisms decomposer
set of related hypotheses supported by evidence theory
Used to produce clear and detailed images of non-living specimens electron microscope
The major energy-carrying molecule in the cell ATP
The lowest level of organization is the _____________________. cell
Particles move randomly from an area of high concentration to an area of low concentration during ____________________________. diffusion
Pairs of chromosomes are called ______________________________________. homologous chromosomes
When oxygen breaks down food to release energy, it is called ______________________________. cellular respiration
the reason that most cells are limited to a very small size surface area-to-volume ratio
small bodies in a cell’s cytoplasm that are specialized to perform specific functions organelles
an organism that consists of a single cell that does not have a nucleus or membrane-bound organelles prokaryote
prokaryotes that include extremophiles, organisms that live in extreme conditions archaebacteria
an organism made up of cells that have a nucleus enclosed by a membrane as well as membrane-bound organelles eukaryote
an organelle that functions as the main power source of a cell, breaking down sugar to produce energy mitochondria
organelles in which photosynthesis takes place chloroplast
If an allele in a Punnett square is written Bt, ______ is the dominant trait. B
In the second generation, ____________________________ reappear after disappearing in the first generation. recessive traits
When sequences of base pairs are copied incorrectly, they are called a_______________________. mutation
Examples of chemical _________________________ include asbestos and chemicals in cigarette smoke. mutagens
The pairing of bases allows cells to __________________________. replicate
Adenine and ____________________________ bases fit together. thymine
Cytosine and ____________________________ bases fit together. guanine
If there is 30% cytosine in a sample, there will be 20% ________________________________. adenine
fertilization of one plant to another cross-pollination
when one trait is not completely dominant over another incomplete dominance
a way to organize possible offspring combinations Punnett square
an organism’s appearance phenotype
the entire genetic makeup of an organism genotype
the mathematical chance that something will happen probability
process that produces cells with half the number of chromosomes meiosis
process where the nucleus divides once mitosis
cell organelle where protein is synthesized ribosome
the form of mutation where one base is replaced by another kind substitution
material shaped like a double helix that determines inherited characteristics DNA
the material made of amino acids that causes most of the differences we see in organisms proteins
bacteria that break down dead organisms decomposer
an organism with no nucleus prokaryote
an organism that invades a cell and uses it to create more organisms virus
bacteria that cause disease pathogenic bacteria
type of cell in which viruses reproduce host
a protist that makes its own food. producer
a protist that invades another organism to get the nutrients it needs parasite
An animal that has a backbone. vertebrate
an organ in fish that removes oxygen from the water and exchanges it with carbon dioxide from the blood. gills
saclike organ that takes oxygen from the air and delivers it to the blood lung
a mammal that lays eggs monotreme
a mammal with a pouch, such as a kangaroo, koala, or opossum marsupial
the muscle that helps bring air into the lungs diaphragm
a soft feather that provides warmth down
a stiff outer feather that determines shape contour
the upward pressure on wings lift
the act of sitting on a nest to keep eggs warm brooding
Created by: missdietrich