SBI4U Unit 1

CARD 1 — ISOTOPES | A) What are isotopes? List the three common isotopes of hydrogen. B) What are radioisotopes? C) How are radioisotopes useful?

A) Atoms of the same element with different numbers of neutrons. Hydrogen has protium (0 neutrons), deuterium (1), and tritium (2). B) Unstable isotopes that release radiation as they decay. C) Used in medical imaging, treatments, and scientific research.

CARD 2 — CHEMICAL BONDS | A) How do ionic and covalent bonds differ? B) What makes a covalent bond polar? C) How do polar and nonpolar covalent bonds differ?

A) Ionic bonds involve attraction between oppositely charged ions formed by electron transfer. Covalent bonds involve sharing electrons. B) A difference in electronegativity causes unequal sharing of electrons. C) Polar bonds share electrons unequally, while nonpolar bonds share electrons equally or nearly equally.

CARD 3 — POLARITY AND PHYSICAL PROPERTIES | A) How does molecular shape affect polarity? B) How do polarity and intermolecular forces affect physical properties? C) How do molecular size and shape affect physical properties?

A) Shape determines whether bond dipoles cancel or create an overall uneven charge. B) Stronger intermolecular forces generally increase boiling and melting points. Polarity also affects solubility. C) Larger molecules often have stronger dispersion forces, and shapes with more contact area can create stronger attractions.

CARD 4 — INTERMOLECULAR FORCES | A) What are the three types of intermolecular forces? B) What is hydrogen bonding? C) Why are hydrogen bonds important in water?

A) London dispersion forces, dipole-dipole forces, and hydrogen bonding. B) An attraction involving hydrogen bonded to N, O, or F and a nearby electronegative atom. C) Hydrogen bonds contribute to water's high boiling point, cohesion, and surface tension.

CARD 5 — OXYGEN | How does oxygen affect A) Bond polarity? B) Bond shape? C) Redox reactions?

A) Oxygen strongly attracts shared electrons, creating polar bonds. B) Oxygen often forms two bonds and has two lone pairs, producing a bent shape in molecules like water. C) Oxygen often accepts electrons, causing another substance to become oxidized.

CARD 6 — DEHYDRATION AND HYDROLYSIS | A) What is dehydration synthesis? B) What is hydrolysis? C) How are these reactions related?

A) Dehydration synthesis joins smaller molecules by removing water. B) Hydrolysis breaks larger molecules apart by adding water. C) They are opposite reactions. Dehydration builds larger molecules, while hydrolysis breaks them down. Remember to practise drawing both reactions.

CARD 7 — PROPERTIES OF WATER | A) Why does water have a high boiling point? B) Why does water have high surface tension? C) What is adhesion? D) Why is ice less dense than liquid water?

A) Hydrogen bonds require extra energy to overcome. B) Hydrogen bonds cause strong cohesion between water molecules. C) Adhesion is water's attraction to other substances. D) Hydrogen bonds create an open lattice in ice, spacing molecules farther apart.

CARD 8 — WATER AS A SOLVENT | A) Why does water dissolve ionic and polar substances? B) Does water form a surface layer around octane? Explain.

A) Water's partial charges attract and surround ions and polar molecules. B) Water can surround octane, but it does not attract octane strongly because octane is nonpolar. Water molecules mainly hydrogen-bond with each other, so octane dissolves poorly.

CARD 9 — ACIDS AND BASES | A) How do acids and bases behave in water? B) What is the difference between strong and weak acids or bases? C) What is neutralization?

A) Acids increase H3O+ concentration. Bases accept H+ or increase OH− concentration. B) Strong acids and bases ionize or dissociate almost completely; weak ones do so partially. C) An acid and base react, usually producing water and a salt.

CARD 10 — BUFFERS AND VITAMIN C | A) What are buffers, and why are they important? B) What does the name ascorbic acid tell us about vitamin C? C) What properties might you notice when eating pure vitamin C?

A) Buffers resist large changes in pH and help cells and enzymes function properly. B) Vitamin C is an acid that can donate H+ in water. C) It has a sour taste and acidic properties.

CARD 11 — FUNCTIONAL GROUPS | A) What is the main purpose of functional groups? B) What role does oxygen play in most functional groups? C) Name three functional groups and their properties.

A) They determine many chemical properties and reactions of organic molecules. B) Oxygen creates polarity and allows hydrogen bonding with water. C) Hydroxyl (–OH): polar; carboxyl (–COOH): acidic; amino (–NH2): basic.

CARD 12 — FUNCTIONAL GROUPS IN WATER | How do these functional groups behave in water? A) Carboxyl B) Amino C) Phosphate

A) Carboxyl releases H+ and becomes –COO−. Equation: R–COOH + H2O ⇌ R–COO− + H3O+. B) Amino accepts H+ and becomes –NH3+. Equation: R–NH2 + H2O ⇌ R–NH3+ + OH−. C) Phosphate can release H+ and become negatively charged. Equation: R–O–PO3H2 + H2O ⇌ R–O–PO3H− + H3O+.

CARD 13 — REACTION EXAMPLES | A) Give a specific example of dehydration synthesis. B) Give a specific example of hydrolysis. C) How can you identify each reaction?

A) Two glucose molecules join to form maltose and water: 2C6H12O6 → C12H22O11 + H2O. B) Maltose breaks into two glucose molecules using water: C12H22O11 + H2O → 2C6H12O6. C) Dehydration releases water and joins molecules. Hydrolysis uses water to break molecules apart.

CARD 14 — ISOMERS | A) What are isomers? B) Which molecules in Figure 13 on page 38 are isomers? C) Why are they isomers?

A) Molecules with the same molecular formula but different arrangements of atoms. B) Molecules (i), (iii), and (iv). C) They all have the molecular formula C6H12O6 but different structures.

CARD 15 — CARBOHYDRATES VS. LIPIDS | A) How does carbohydrate structure affect its properties and uses? B) Compare the polarity of carbohydrates and lipids. C) Why are most polysaccharides insoluble in water?

A) Their many –OH groups make them polar. Small carbohydrates can provide quick energy, while larger ones store energy or provide structure. B) Carbohydrates are generally polar and hydrophilic; lipids are mostly nonpolar and hydrophobic. C) Their large size and strong attractions between chains can limit their solubility.

CARD 16 — FATS AND STEROIDS | A) What is the difference between a fatty acid and a fat? B) What happens to a fatty acid's acidic properties when a fat forms? C) Why are steroids important?

A) A fatty acid is one component of a fat. A fat usually contains glycerol and three fatty acids. B) Its carboxyl group forms an ester bond and no longer acts as a free acid. C) Steroids such as cholesterol help maintain membranes, and some steroids act as hormones.

CARD 17 — AMINO ACIDS AND PROTEINS | A) What groups are found in every amino acid? B) What is primary protein structure? C) What is secondary protein structure?

A) An amino group, carboxyl group, hydrogen atom, and variable R group attached to a central carbon. B) The specific sequence of amino acids. C) Local folding into alpha helices or beta sheets, stabilized by hydrogen bonds.

CARD 18 — PROTEIN FUNCTIONS | A) What are four types of proteins and their functions? B) Give specific examples of proteins in living organisms.

A) Enzymes speed up reactions, structural proteins provide support, transport proteins carry substances, and antibodies help defend against pathogens. B) Amylase digests starch, collagen provides support, hemoglobin transports oxygen, and antibodies help fight infections.

CARD 19 — DNA VS. RNA | A) What similarities do DNA and RNA share? B) How do they differ in structure? C) How do their functions differ?

A) Both are nucleic acids made of nucleotides containing a sugar, phosphate, and nitrogenous base. B) DNA contains deoxyribose and thymine and is usually double-stranded. RNA contains ribose and uracil and is usually single-stranded. C) DNA stores genetic information, while RNA helps use that information to make proteins.

CARD 20 — CELL TYPES | A) What is the main difference between prokaryotic and eukaryotic cells? B) Why is this difference important? C) What is an organelle?

A) Eukaryotic cells have a nucleus and membrane-bound organelles; prokaryotic cells do not. B) Organelles allow eukaryotic cells to separate and specialize cellular activities. C) A specialized cellular structure that performs a specific function.

CARD 21 — CELL STRUCTURE RELATIONSHIPS | Explain the relationship between A) Endoplasmic reticulum and nuclear envelope. B) Centrioles and microtubules. C) Ribosomes and nucleolus. D) Plastids and pigments.

A) The outer nuclear membrane is continuous with the ER. B) Centrioles are made of microtubules and help organize structures during cell division. C) The nucleolus assembles ribosomal subunits, which help make proteins. D) Some plastids contain pigments, such as chlorophyll in chloroplasts.

CARD 22 — ENDOPLASMIC RETICULUM | A) What does rough ER do? B) What does smooth ER do? C) What is their main difference?

A) Rough ER has ribosomes and helps produce and process proteins. B) Smooth ER makes lipids, stores calcium, and helps detoxify substances. C) Rough ER has ribosomes and specializes in protein production, while smooth ER lacks ribosomes and performs other functions.

CARD 23 — MITOCHONDRIA | A) What are mitochondria? B) Describe their structure. C) Why are they called the power plants of cells?

A) Organelles that carry out aerobic cellular respiration. B) They have an outer membrane, a folded inner membrane called cristae, and a fluid-filled matrix. C) They produce most of the ATP used by cells.

CARD 24 — FLUID MOSAIC MODEL | A) What is the Fluid Mosaic Model? B) How are phospholipids arranged? C) How does membrane structure help its function?

A) A flexible phospholipid bilayer containing proteins and other molecules that can move within it. B) Hydrophilic heads face water, while hydrophobic tails face inward. C) The bilayer forms a selective barrier, while proteins help with transport and communication.

CARD 25 — STEROLS AND CHOLESTEROL | A) What is the function of sterols in membranes? B) Which sterol is found in animal cell membranes? C) Is cholesterol polar or nonpolar, and how is it positioned?

A) Sterols help regulate membrane fluidity and stability. B) Cholesterol. C) Cholesterol is mostly nonpolar with a small polar –OH group. The –OH group stays near phospholipid heads, while the nonpolar portion sits among fatty acid tails.

CARD 26 — MEMBRANE COMPONENTS | What are the functions of A) Phospholipids? B) Membrane proteins? C) Membrane carbohydrates?

A) Phospholipids form the bilayer and act as a selective barrier. B) Proteins help with transport, enzyme activity, signalling, and attachment or recognition. C) Carbohydrates help with cell recognition, identification, and communication.

CARD 27 — OSMOSIS | A) What is osmosis? B) Why is distilled water hypotonic to body cells? C) What happens to a red blood cell placed in distilled water?

A) Osmosis is the movement of water across a selectively permeable membrane. B) Distilled water has a lower solute concentration than the inside of the cell. C) Water enters by osmosis, causing the cell to swell and possibly burst.

CARD 28 — PASSIVE VS. ACTIVE TRANSPORT | Compare the energy requirements of A) Passive transport. B) Primary active transport. C) Secondary active transport.

A) Passive transport requires no cellular energy and moves substances down their gradients. B) Primary active transport directly uses energy, usually from ATP, to move substances against their gradients. C) Secondary active transport uses energy stored in an ion gradient created by primary active transport.

CARD 29 — ENDOCYTOSIS AND EXOCYTOSIS | A) What process is shown in Figure 13 on page 97? B) What is endocytosis? C) What is exocytosis?

A) Endocytosis. B) The cell membrane folds inward and brings materials into the cell by forming a vesicle. C) A vesicle fuses with the cell membrane to release materials outside the cell. For the drawing: label the membrane folding inward, cytoplasm, and the vesicle forming inside the cell.

CARD 30 — IMPORTANCE OF TRANSPORT | How does membrane transport help A) Red blood cells? B) Cells in the gut? C) The release of hormones?

A) Red blood cells exchange oxygen and carbon dioxide and maintain water balance. B) Gut cells absorb nutrients such as glucose. C) Hormones are released through exocytosis when secretory vesicles fuse with the cell membrane.