science exam revision

Question 1

what does dna stand for

Answer 1

Deoxyribonucleic acid

Question 2

what are the four different types of bases

Answer 2

adenine, cytosine, guanine and thymine

Question 3

what are the base pairs

Answer 3

A and T and G and C

Question 4

whats in a nucleotide

Answer 4

one sugar (deoxyribose), one phosphate and a base pair

Question 5

where is a molecule found

Answer 5

in the nucleus of a cell

Question 6

what is a chromosome

Answer 6

long threads of dna

Question 7

what is a gene

Answer 7

a section of a chromosome that gives instructions for a feature. it’s also a unit of dna that makes a protein.

Question 8

how is a protein made

Answer 8

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.

Question 9

whats dna made up of

Answer 9

nucleotides

Question 10

whats protein made up of

Answer 10

amino acids

Question 11

how many nucleotides are in an amino acid and what are they called

Answer 11

three, and they’re called triplets

Question 12

whats a mutation

Answer 12

a permanent change in the order of the bases in the dna

Question 13

whats a mutagen

Answer 13

any agent that could cause a mutation

Question 14

what is point mutation

Answer 14

when there is a substitution in a single base (one base is replaced with another)

Question 15

whats a silent mutation

Answer 15

a base where theres a substitution, resulting in the same amino acid

Question 16

whats a frameshift mutation

Answer 16

a mutation created when bases are added or deleted.

Question 17

what are the three different types of chromosome mutations

Answer 17

deletion, inversion and translocation

Question 18

what is a deletion, inversion and translocation

Answer 18

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.

Question 19

whats a karyotype

Answer 19

the process of pairing and ordering all the chromosomes of an organism

Question 20

whats mitosis

Answer 20

the division of body cells, which produces 2 diploid cells

Question 21

whats meiosis

Answer 21

the division of cells to produce gametes, which produces 4 haploid cells

Question 22

whats the formula for displacement

Answer 22

displacement = final position - initial position

Question 23

whats the formula for speed

Answer 23

distance/time

Question 24

whats the formula for velocity

Answer 24

displacement/time

Question 25

whats the formula for acceleration

Answer 25

change of velocity/time

Question 26

what are the three types of motion graphs

Answer 26

x-t, v-t and a-t

Question 27

what type of motion graph is x-t

Answer 27

position-time

Question 28

what type of motion graph is v-t

Answer 28

velocity-time

Question 29

what type of motion graph is a-t

Answer 29

acceleration-time

Question 30

what are the horizontal rows and vertical columns called in the periodic table

Answer 30

horizontal rows are periods and vertical columns are groups

Question 31

what is group 1

Answer 31

alkali metals

Question 32

what is group 2

Answer 32

alkali earth metals

Question 33

what are groups 3-12

Answer 33

transition metals

Question 34

what is group 17

Answer 34

halogens

Question 35

what is group 18

Answer 35

noble gases

Question 36

what are the three types of bonding

Answer 36

covalent bonding (non-metal), metallic bonding (metals) and ionic bonding (non-metals and metals)

Question 37

when does a metal become a positive ion

Answer 37

when it loses electrons, because it has more protons than electrons, making it a positive ion (becomes a cation)

Question 38

when does a metal become a negative ion

Answer 38

when it gains an electron because it has more electrons than protons, making it negative. (becomes an anion)

Question 39

how are ionic compounds named

Answer 39

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

Question 40

whats a catalyst

Answer 40

any chemical that helps speed up a reaction, but doesn’t participate and isn’t directly changed in the reaction

Question 41

what are different rates of reaction

Answer 41

-more surface area
-agitation (stirring)
-temperature/heat
-concentration (how much a chemical solution can dissolve)