science exam revision Flashcards
what does dna stand for
Deoxyribonucleic acid
what are the four different types of bases
adenine, cytosine, guanine and thymine
what are the base pairs
A and T and G and C
whats in a nucleotide
one sugar (deoxyribose), one phosphate and a base pair
where is a molecule found
in the nucleus of a cell
what is a chromosome
long threads of dna
what is a gene
a section of a chromosome that gives instructions for a feature. it’s also a unit of dna that makes a protein.
how is a protein made
a copy of a gene is made in the nucleus, then the copy travels out of the nucleus to the ribosomes, and the ribosomes using the copy make a protein.
whats dna made up of
nucleotides
whats protein made up of
amino acids
how many nucleotides are in an amino acid and what are they called
three, and they’re called triplets
whats a mutation
a permanent change in the order of the bases in the dna
whats a mutagen
any agent that could cause a mutation
what is point mutation
when there is a substitution in a single base (one base is replaced with another)
whats a silent mutation
a base where theres a substitution, resulting in the same amino acid
whats a frameshift mutation
a mutation created when bases are added or deleted.
what are the three different types of chromosome mutations
deletion, inversion and translocation
what is a deletion, inversion and translocation
deletion is when part of a chromosome breaks off, taking genes with it.
inversion is when part of a chromosome breaks off then rejoins
translocation is when part of a chromosome moves and attaches to another.
whats a karyotype
the process of pairing and ordering all the chromosomes of an organism
whats mitosis
the division of body cells, which produces 2 diploid cells
whats meiosis
the division of cells to produce gametes, which produces 4 haploid cells
whats the formula for displacement
displacement = final position - initial position
whats the formula for speed
distance/time
whats the formula for velocity
displacement/time
whats the formula for acceleration
change of velocity/time
what are the three types of motion graphs
x-t, v-t and a-t
what type of motion graph is x-t
position-time
what type of motion graph is v-t
velocity-time
what type of motion graph is a-t
acceleration-time
what are the horizontal rows and vertical columns called in the periodic table
horizontal rows are periods and vertical columns are groups
what is group 1
alkali metals
what is group 2
alkali earth metals
what are groups 3-12
transition metals
what is group 17
halogens
what is group 18
noble gases
what are the three types of bonding
covalent bonding (non-metal), metallic bonding (metals) and ionic bonding (non-metals and metals)
when does a metal become a positive ion
when it loses electrons, because it has more protons than electrons, making it a positive ion (becomes a cation)
when does a metal become a negative ion
when it gains an electron because it has more electrons than protons, making it negative. (becomes an anion)
how are ionic compounds named
first with the cation which has the same name as the element, then the anion which has the stem of the element followed by ‘ide’. e.g: sodium oxygen = sodium oxide
whats a catalyst
any chemical that helps speed up a reaction, but doesn’t participate and isn’t directly changed in the reaction
what are different rates of reaction
-more surface area
-agitation (stirring)
-temperature/heat
-concentration (how much a chemical solution can dissolve)
