Download Science Exam Review Answer Key

Science Exam Review Answer Key
Asexual/Sexual Reproduction
1. Healing and tissue repair, growth and reproduction of the organism.
2. Cytosine, Adenine, Thymine and Guanine.
3. Chromosomes are double stranded coiled up DNA (Genetic Information).
4. Genes make up DNA, DNA make up the chromosomes, chromosomes are
found in the nucleus of the cell.
5. The individual is identical to the parent.
6. They inherit traits from both parents which makes them a unique individual.
7. Binary fission: is a quick reproduction where cells split to form 2 cells. Ex)
Bacteria
Fragmentation: is when small pieces break off an individual to produce a
new organism. Ex) mushrooms
Budding: a bud forms, grows and breaks away Ex) Yeast
8. Interphase: Copy DNA, cell gets bigger
Prophase: DNA becomes chromosomes, chromosomes become thick,
nuclear membrane disappears, spindle fibres from
Metaphase: spindle fibres tug double stranded chromosomes to middle
Anaphase: spindle fibres shorten causing the chromosomes to move to
opposite sides of the cell
Telophase: spindle fibres disappear, chromosomes uncoil, nuclear membrane
forms around each new set of chromosomes, cell splits, 2 new cells
9. Telophase. Cell division is important after mitosis because we need to create
two new cells so that each new set of DNA has its own cell.
10. Regeneration – when an organism is divided into fragments (pieces). In
animals – starfish are capable of growing back and arm that is cut off, that
piece will also become a starfish. In humans – muscle is capable of
regeneration; also our hair, skin, and nails are constantly regenerating.
11. DNA
12. It is important that cells increase in number instead of size, because if they
were to just grow bigger they would not be able to function properly because
the nucleus would be to far from the other parts of the cell so it would not
be able to communicate with them and also the cell would not be able to
keep up with waste removal.
13. Advantage: no partner, offspring more viable, quickly colonize, energy used
to produce offspring
Disadvantage: no genetic variability means that if there is a catastrophe the
entire population will die.
14. Sea stars reproduce asexually so if you cut their arm off, that arm will
develop into another sea star and the cut sea star will grow another arm.
15. Reproductive cells (or sex cells or gametes).
16. Meiosis results in 4 cells, mitosis 2.
Meiosis sister chromatids do not pull apart but in mitosis they do.
Meiosis during metaphase homologous pairs line up in the middle, whereas
in mitosis only single chromosomes line up along the middle.
17. Haploid cells contain 23 chromosomes. Diploid contain 23 pairs of
chromosomes which means in total they have 46. In humans sex cells are
haploid and body cells are diploid.
18. Male gametes are sperm. Female gametes are eggs. It is important that they
are haploid so that when they combine the new resulting cell has 46
chromosomes, 23 from each sex cell.
19. It is called fertilization. The resulting cell is called a zygote.
20. Human gametes have 23 chromosomes and human cells 46. It is important
that gametes have only 23 chromosomes so that when the female and male
gametes combine the resulting cell has 46 chromosomes.
21. Moisture is important so that the egg and sperm don’t dry out, so that the
eggs cell membrane stays supple so that the sperm can pierce it, and the
sperm can only swim in wet environment.
22. Homologous pairs
23. Flowers – angiosperms
No flowers – gymnosperms
24. male – anther, female – ovary
25. Pollination
26. Self-pollination – when both the male and female gametes come from the
same plant. Cross-pollination – when the male and female gametes come
from different plants.
27. Fish, frogs, coral.
28. An animal that has both male and female reproductive organs.
Genetics and Biotechnology
29. Genetics: characteristics that are passed on from generation to generation.
Traits: a distinct type of characteristic you have, like eye colour.
Phenotype: how an organism looks, functions, or behaves. (word)
Genotype: the actual genes present in the chromosome. (letter)
Dominant genes: the genes that over powers the recessive genes. Only one
is required to show as a phenotype in the organism.
Recessive genes: the genes that are overpowered by dominant genes. Two
are required to show as a phenotype in the organism.
Homozygous: when both genes are the same.
Heterozygous: when the two genes are different.
Sex chromosomes: determine whether you are female or male. In a male
they are XY and in a female they are XX.
Sex linked traits: traits carried on the X chromosome.
Sex limited trait: traits carried on the Y chromosome.
30. a) Genotype: CC, phenotype: curly hair, homozygous
b) Genotype: Cc, phenotype: curly hair, heterozygous
c)
Dad
Mom
C
c
C
CC
Cc
c
Cc
cc
d)
Mom
Dad
C
C
C
CC
CC
c
Cc
Cc
The offspring would be 50% homozygous dominant, 50% heterozygous.
31. Sex linked punnett square
XN
XN Xn
XN
XNXn
XN Y
XNY
Xn
Y
32. Deletion, Insertion, Duplication and Inversion.
Atoms and Elements
1. Democritus – thought the material world was made of atoms.
Aristotle & Empedicoles – 4 element theory. Everything was made of wind,
water, air and fire.
Alchemists – They were part magician, part chemists. First people to
experiment.
2. Billiard ball model: John Dalton, called this because he believed atoms were
hard and indestructible.
Plum pudding model: Joseph Thomson, called this because he believed that
protons and electrons were scattered throughout a solid mass, similar to
plums in raisins.
Planetary model: Bohr, proposed that electrons orbit around the nucleus like
planets orbiting the Sun.
Nuclear model: Ernest Rutherford, called this because all protons are in the
nucleus and the electrons float around in an “electron cloud”.
3. Mendeleev. Row – period, column – family.
4. If elements are arranged according to atomic mass, a pattern can be seen
where similar characteristics occur regularly.
5. Protons – positive – nucleus
Electrons – negative – electron shell
Neutron – neutral – nucleus
6. The second letter should not be capitalized.
7.
Number
Number
Number
Atomic
Atomic
Element
Chemical
of protons of
of
mass of
number
name
symbol
in the
electrons
neutrons
the atom
of the
atom
in the
in the
atom
atom
7
7
7
14
7
Nitrogen
N
8
8
8
16
8
Oxygen
O
43
43
55
98
43
Technetium Tc
16
16
16
32
16
Sulfur
S
20
20
20
40
20
Calcium
Ca
19
19
20
39
19
Potassium
K
13
13
14
27
13
Aluminum
Al
23
23
28
51
23
Vanadium
V
atom
8. *** Come see me if you want to see the picture***
Ne - Atomic number 10, Mass 20: 1st ring-2, 2nd ring-8
** Don’t do this one. K - Atomic number 19, Mass 39: 1st ring-2, 2nd ring8, 3rd ring-8, 4th ring-1
Al - Atomic number 13, Mass 27: 1st ring-2, 2nd ring-8, 3rd ring-3
B - Atomic number 5, Mass 11: 1st ring-2, 2nd ring-3
O - Atomic number 8, Mass 16: 1st ring-2, 2nd ring-6
N - Atomic number 7, Mass 12: 1st ring-2, 2nd ring-5
9. Valence electrons are the electrons that are found in the outermost shell. For
example Nitrogen would have 5 valence electrons.
10. I would look at the atomic number, which is equal to the number of protons
in the atom, and the atomic mass. If I subtract the mass from the atomic
number that is equal to the number of neutrons in the atom.
Atomic mass – Atomic number = neutrons.
11. A compound is the simplest form of a material that contains two or more
elements in a fixed proportion.
12. a) Na2SO4
b) PCl3
c) PbNO3
Na=2 S=1
O=4
Total=7
P=1
Cl=3
Total=4
Pb=1 N=1
O=3
Total=5
13. Physical changes: the substance remains the same even though it may
change state or form.
Chemical changes: during reaction the original substance is changed into
one or more different substances that have different properties.
Three ways you can tell a chemical change has taken place: heat loss or
gain, light emission, bubbles, colour change, precipitate forms, changes that
are difficult to reverse.
14. Physical change: melting chocolate, releasing the bubbles (CO2) out of
soda.
Chemical change: baking a cake, leaves turning brown.
15. The more electrons the atom needs to fill its outer shell the more reactive it
is. For example, if the atom has 7 electrons in its outer shell, it is going to
be very reactive because it needs only 1 more electron to be stable.
It is also this way for atoms that only need to lose 1 electron in order to be
stable.
This is why atoms in the alkali metals and halogens are extremely reactive.
16. Metals – lustre, silver-grey colour (2 exceptions), malleable, ductile, solid,
conduct heat and electricity.
Non-metals – no lustre, brittle, insulators or noncondutors, usually either
solid or gas.
Metalloids – solid, some have lustre, behave like non-metals in their physical
properties, semiconductors.
17. Na and Cl are extremely reactive on their own because Na has one electron
to give away for a stable shell and Cl requires one to have a complete shell.
When they bond they both become stable and form salt. Before they bond
they each have their own unique properties, and once bonded the compound
has new properties.
Astronomy
1. Day and night is caused by the Earth rotating on its axis away from the sun.
Day is when we are facing the sun and night is when we are away.
2. B
3. New moon, waxing crescent, first quarter, waxing gibbous, full moon, waning
gibbous, third quarter, waning crescent.
4.
New moon – moon is between the earth and sun
1st quarter and 3rd quarter – moon makes 90 degree angle with the sun and the
earth
Full moon – moon is on the opposite side of the earth from the new moon
5. Gibbous – moon is more than half illuminated
Crescent – moon is less than half illuminated
Waxing – part of the moon that is lit up is shrinking
Waning – part of the moon that is lit up is growing
6. D. Just after sunset
7. B. The moon rises in the east.
8. Tides are caused by the earth being attracted to the sun and moon like
magnets. The only thing that can be pulled by the gravity of the sun and
moon is the water.
9. Seasons are caused by the tilt of the earth. As the earth revolves around
the sun the tilt allows for certain hemispheres to receive more direct sunlight
and for more sunlight throughout the day.
10. The sun is in the sky longer and the suns rays hit more directly.
11. It takes the earth one year to revolve around the sun.
12. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
13. Milky Way
14. Planets are sphere in shape because they give into the gravitational pull
from the center of the planet. Planets want to have all the mass as close to
the center of gravity as possible.
15. 1 year is 365 days, or the time it takes the Earth to make on revolution
around the Sun. 1 day is 24 hours, or the time it takes Earth to make one
rotation.
16. It takes the moon approximately 29.5 days.
17. No, we only see one side of the moon because of the time it takes the
moon to make a rotation.
18. The moon rises in the East and sets in the West because of the rotation of
the Earth and the way the Moon revolves around it.