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86 terms

9th grade biology midterm

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Transformation
process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria
bacteriophage
virus that infects bacteria
nucleotide
monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
base pairing
principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine
chromatin
granular material visible within the nucleueus: consists of DNA tightly coiled around proteins
histone
globular protein molecule around wihch DNA is tightly coiled in chromatin
replication
copying process by which a cell duplicates its DNA
DNA polymerase
enzyme that profreads new DNA strands, helping to ensure that each molecule is a neraly perfect copy of the original DNA
gene
sequence of DNA that codes for a protein and this determines a trait
messenger RNA
RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell
ribosomal RNA
type of RNA that makes up the major part of ribosomes
transfer RNA
type of RNA molecule that transfers amino acids to ribosomes during protein synthesis
transcription
process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA
RNA polymerase
enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription
SEM
scanning electon microscopes shine a narrow beam of electrons BACK AND FORTH a thin specimen's SURFACE
TEM
transmission electron microscope shines a beam THROUGH a specimen and gives a detailed picture of the INSIDE of a cell
atom-3 parts
smallest unit of matter consisting of protons(positive charge), neutrons(neutral charge), electons(negative charge)
carbohydrates
main source of energy in living things are made up of compounds made of carbon, hydrogen and oxygen atoms
lipids
large group of organic compounds that make up fats, hormones, and building blocks of the cell membrane
cell theory
all living things are composed of cells and all new cells are produced from existing cells
prokaryotes
cells that have genetic material that isn't contained in a nucleus-example bacteria
eukaryotes
cells that contain a nucleus in which their genetic material is separated from the rest of the cell, except bacteria
nucleus
contains nearly all of the cells DNA and with it the coated instructions for making proteins and other important molecules
lysosomes
small organelles filled with enzymes that helps digest foreign particles
chloroplasts
organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis
autotroph
organisms which make their own food, such as plants
heterotroph
organisms such as animals which cannot use the sun's energy directly
ATP
consists of adenine, a 5-carbon sugar called ribose, and 3 phosphate groups, also high energy bonds between the 2nd and 3rd phosphate groups
granum
stack of thylakoids
stroma
Calvin Cycle takes place here, where sugars are produced
promoter
region of DNA that indicates to an enzyme where to bind to make RNA
intron
intervening sequence of DNA:does not code for a protein
exon
expressed sequence of DNA: codes for a protein
codon
3 nucleotide sequence on messenger RNA that codes for a single amino acid
translation
decoding of mRNA message into a polypeptide chain
anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA codon
mutation
change in a DNA sequence that affects genetic information
point mutation
mutation that affects a single nucleotide, usually by substituting one nucleotide for another
polyploidy
condition in which an organism has extra sets of chromosomes
karyotype
set of photographs of chromosomes grouped in ordered pairs
sex chromosome
one of two chromosomes that determine an individuals sex
autosome
a chromosome that is not a sex chromosome, 44 of these
pedigree
a charge that shows the relationships within a faimly
sex-linked gene
gene located on the x or y chromosome
nondisjuction
error in meiosis in which homologous chromosomes fail to separate
DNA fingerprinting
an analysis of sections of DNA that have little or not function, but vary widely from individual to another in order to identify individuals
genetics
the scientific study of heredity
fertilization
during sexual reproduction, male and female reproductive cells join
true breeding
if allowed to self pollinate, they would produce offspring identical to themselves
trait
specific characteristiv, such as seed color or plant height, that varies from one individula to anoth
Hybrids
the offspring of crosses betwenn parents with different traits
Genes
the chemical factors that determine traits
Alleles
the different forms of a gene
Segregation
separation
Gametes
sex cells
Probability
the likelihood that a particular event will occur
Punnet square
A drawing diagram that shows gene combinations that might result from a genetic cross
Homozygous
organisms that have two same alleles for the same trait
Heterozygous
organisms that have two different alleles for the same trait
Phenotype
physical characteristics
Genotype
genetic makeup
Incomplete dominance
were one allele is not completely dominant over another
Codominance
both alleles contrubute to the phenotype.
Multiple alleles
When genes have more than two alleles
Polygenic traits
having many genes
Mitosis
the first stage, division of the cell nucleus
Cytokinesis
the second stage, division of the cytoplasm
Chromatid
identical sister structures, two of which are contained in each chromosome
Centromere
usually located near the middle of the chromatids, although some lie near the ends
Interphase
"in between" period of growth
Cell Cycle
the series of events that cells fo through as they grow and divide
Prophase
can take as much as 50 to 60 percent of the total time required to complete
Centrioles
two tiny structures located in the cytoplasm near the nuclear envelope seperate and take up position on opposite sides of the neucleus
Spindle
a fanlike microtube structure that helps seperate the chromosomes
Metaphase
the chromosomes line up accross the center of the cell
Anaphase
centromeres that join the sister chomatids split, allowing the sister chromatids to separate and become individual chromosomes
Telophase
Fourth and final phas, Chromosomes which were distinct and condensed, begin to disperse into a tangle of dense material
Cyclin
protein which regulates the cell cycle
Cancer
a disorder in which some of the bodys own cells loses the ability to control growth is one such such example
Homologue
each of teh 4 chromosomes that came from the male parent has a corresponding chromosome from the female parent
Diploid
a cell that contains both sets of homologous chromosomes
Haploid
one set
Meiosis
a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
Tetrad
in prophase of meiosis 1, each chromosome pairs with its corresponding homologous chromosome to form a tetrad
Crossing over
When homologous chromosomes pair up and form tetrads in meiosis 1, they exchang portions of their chromatids in a process called crossing-over
Gene map
showing the relative locations of each know gene on one of the Drosophila chromosomes