science exam- semester 1

Question 1

Identify the function of the nucleus in animal cells.

Answer 1

Contains DNA and controls cell activities.

Question 2

Identify the function of mitochondria in animal cells.

Answer 2

Site of cellular respiration; produces energy (ATP).

Question 3

Identify the function of ribosomes in animal cells.

Answer 3

Site of protein synthesis.

Question 4

Identify the function of the cell membrane in animal cells.

Answer 4

Controls movement of substances in and out of the cell.

Question 5

State the full name of DNA.

Answer 5

Deoxyribonucleic acid.

Question 6

Describe the structure of a nucleotide.

Answer 6

Phosphate group, deoxyribose sugar, and nitrogenous base. Adenine, cytosine, guanine, thymine, bases

Question 7

Describe how nucleotides join to form DNA

Answer 7

Nucleotides form a sugar-phosphate backbone; bases pair as A-T and C-G.

Question 8

Describe the relationship between DNA, genes and chromosomes.

Answer 8

All interconnected parts of an organism’s genetics, working together to transmit information

Question 9

Describe the function and process of mitosis.

Answer 9

Cell division producing two identical daughter cells for growth and repair.

Question 10

List and describe the stages of mitosis.

Answer 10

Prophase: chromosomes shorten + thicken
Metaphase: chromosomes line up at the centre of the cell
Anaphase: sister chromatids separate + move
Telophase: reach opposite pole, new nuclear envelopes form

Question 11

Describe the function and of meiosis and fertilisation.

Answer 11

Meiosis produces gametes; fertilisation restores full chromosome number

Question 12

Describe the process of meiosis and fertilisation

Answer 12

meiosis: 2 rounds of cell division, then 1 round of DNA replication
meiosis 1- chromosomes pair up and exchange DNA
meiosis 2- sister chromatids are separated, resulting in 4 daughter cells

fertilisation: the fusion of the haploid sperm cells

Question 13

Compare and contrast mitosis and meiosis.

Answer 13

Mitosis: 2 identical cells. Meiosis: 4 unique gametes.

Question 14

Describe the principle of Mendelian inheritance.

Answer 14

certain patterns of how traits are passed from parents to offspring

Question 15

State the law of independent assortment.

Answer 15

Alleles for different traits are distributed independently during gamete information

Question 16

Explain co-dominance and incomplete dominance.

Answer 16

Co-dominance: both alleles shown. Incomplete dominance: blend of traits.

Question 17

Identify ABO blood groups as a co-dominant trait.

Answer 17

A and B alleles are co-dominant; O is recessive.

Question 18

Explain the difference between autosomal inheritance and sex-linked inheritance.

Answer 18

Autosomal: genes on non-sex chromosomes; sex-linked: on X/Y chromosomes.

Question 19

Define the terms: element, atom, atomic number, mass number, isotope.

Answer 19

Element: pure substance. Atom: smallest unit. Atomic #: protons. Mass #: protons + neutrons. Isotope: same protons, different neutrons.

Question 20

Describe the structure of atoms: protons, neutrons, electrons.

Answer 20

Protons and neutrons in nucleus; electrons in shells.

Question 21

State the mass and charge of protons, neutrons, electrons.

Answer 21

Proton: +1, 1 amu; Neutron: 0, 1 amu; Electron: -1, ~0 amu.

Question 22

Use atomic structure notation and isotope names to find protons, neutrons, electrons.

Answer 22

Protons = atomic #; Neutrons = mass # - atomic #; Electrons = protons (neutral atoms).

Question 23

Draw electron shell diagrams for first 20 elements.

Answer 23

Electrons arranged in shells: 2, 8, 8, 2.

Question 24

Write electron configurations for first 20 elements.

Answer 24

E.g. Carbon: 2, 4; Oxygen: 2, 6.

Question 25

Explain periodic table organisation: metals, non-metals, metalloids, groups, periods.

Answer 25

Metals on left, non-metals on right, metalloids in between; groups = columns; periods = rows.

Question 26

Explain the role of atomic number, valence electrons and electron shells in the periodic table.

Answer 26

Atomic number = protons; group = valence electrons; period = number of shells.

Question 27

Identify the location of alkali metals on the periodic table.

Answer 27

Group 1.

Question 28

Identify the location of alkaline earth metals on the periodic table.

Answer 28

Group 2.

Question 29

Identify the location of transition metals on the periodic table.

Answer 29

Center block (Groups 3-12).

Question 30

Identify the location of halogens on the periodic table.

Answer 30

Group 17.

Question 31

Identify the location of noble gases on the periodic table.

Answer 31

Group 18.

Question 32

Explain why atoms form bonds in terms of electron configurations.

Answer 32

To achieve full outer shells (stable configurations).

Question 33

Describe the structure of metallic bonding.

Answer 33

Positive ions in a sea of delocalised electrons.

Question 34

Relate the structure of metals to their properties.

Answer 34

Lustrous, conductive, high melting point, malleable, ductile.

Question 35

Describe the structure of ionic compounds.

Answer 35

Lattice of alternating positive and negative ions.

Question 36

Relate the structure of ionic compounds to their properties.

Answer 36

High melting point, conductive when molten/dissolved, brittle.

Question 37

Write names and formulas for ionic compounds (no polyatomic ions).

Answer 37

E.g. Iron (II) chloride = FeCl₂.

Question 38

Describe the structure of covalent compounds.

Answer 38

Atoms share electrons to form molecules.

Question 39

Relate the structure of covalent compounds to their properties.

Answer 39

Low melting/boiling points, poor conductors, soft.

Question 40

Write names and formulas of covalent compounds.

Answer 40

E.g. H₂O = water, CO₂ = carbon dioxide.

Question 41

I can recall the definition of an element.

Answer 41

A pure substance made of only one type of atom.

Question 42

I can recall the definition of an atom.

Answer 42

The smallest unit of an element that retains its properties.

Question 43

I can recall the definition of atomic number.

Answer 43

The number of protons in an atom.

Question 44

I can recall the definition of mass number.

Answer 44

The total number of protons and neutrons in an atom.

Question 45

I can recall the definition of an isotope.

Answer 45

Atoms of the same element with different numbers of neutrons.

Question 46

I can describe where protons, neutrons and electrons are located in an atom.

Answer 46

Protons and neutrons in the nucleus; electrons in orbitals.

Question 47

I can describe how to calculate the number of protons, neutrons and electrons in isotopes.

Answer 47

Protons = atomic number; neutrons = mass number minus atomic number; electrons = protons (in neutral atoms).

Question 48

I can draw diagrams of electron shells for the first 20 elements.

Answer 48

Fill shells in the order: 2, 8, 8, 2.

Question 49

I can write the electron configurations for the first 20 elements.

Answer 49

E.g. Carbon: 2, 4; Calcium: 2, 8, 8, 2.

Question 50

I can explain how the periodic table is organized.

Answer 50

By increasing atomic number, grouped by properties and electron configurations.

Question 51

I can explain the number of valence electrons using group number.

Answer 51

Group number corresponds to the number of valence electrons (for main groups).

Question 52

I can explain the number of electron shells using the period number.

Answer 52

Period number corresponds to the number of electron shells.

Question 53

I can explain why atoms form chemical bonds.

Answer 53

To attain a full outer electron shell and achieve stability.