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Questions and Answers

Which characteristic of life refers to how organisms maintain a stable internal environment?

Response to Stimuli

Growth and Development

Adaptation through Evolution

Homeostasis (correct)

Which of the following describes a qualitative observation?

Noticing that a leaf is green (correct)

Counting the number of leaves on a tree

Weighing an apple to find it has a mass of 150 grams

Measuring a plant's height as 30 cm

What is the correct order of the steps of the Scientific Method?

Hypothesis, Experiment, Observation, Conclusion, Data Collection, Communication

Question, Experiment, Data Collection, Observation, Conclusion, Communication

Experiment, Observation, Question, Data Collection, Conclusion, Communication

Observation, Question, Hypothesis, Experiment, Data Collection, Conclusion, Communication (correct)

Which substance can be classified as an acid?

Vinegar Signup and view all the answers

What is the primary function of lipids?

Energy storage and insulation Signup and view all the answers

Which of the following correctly defines an element?

A pure substance made of one type of atom Signup and view all the answers

What is the role of amino acids in living organisms?

They are the building blocks of proteins Signup and view all the answers

Which of the following is a correct statement regarding buffers?

They help maintain stable pH levels Signup and view all the answers

What is the main function of ribosomes in a cell?

Protein synthesis Signup and view all the answers

Which statement correctly differentiates between hypertonic and hypotonic solutions?

Hypertonic solutions lead to cell shrinkage. Signup and view all the answers

In photosynthesis, which of the following is a product of the light reactions?

Oxygen Signup and view all the answers

Which part of an angiosperm is responsible for its male reproductive functions?

Stamen Signup and view all the answers

What is the primary role of the mitochondrial organelle in cells?

Cellular respiration Signup and view all the answers

During which stage of interphase does DNA replication occur?

S phase Signup and view all the answers

Which molecule acts as the messenger carrying genetic information from DNA to the ribosome?

mRNA Signup and view all the answers

What type of transport requires energy to move substances against a concentration gradient?

Active transport Signup and view all the answers

Which scientists are credited with discovering the structure of DNA?

James Watson and Francis Crick Signup and view all the answers

What is the correct sequence of stages in cellular respiration?

Glycolysis → Krebs Cycle → Electron Transport Chain Signup and view all the answers

Study Notes

Chapter 1: The Science of Biology

Eight Characteristics of Life:
- Organization: Living things are structured from cells to systems (e.g., cells, tissues, organs, systems in humans).
- Reproduction: Living organisms reproduce (e.g., bacteria by binary fission).
- Growth and Development: Organisms increase in size and complexity over time (e.g., seed to tree).
- Energy Use (Metabolism): Living things use energy (e.g., plants through photosynthesis).
- Response to Stimuli: Organisms react to their environment (e.g., sunflowers facing sunlight).
- Homeostasis: Maintaining a stable internal environment (e.g., human body temperature regulation).
- Adaptation through Evolution: Populations change over generations (e.g., antibiotic resistance).
- Genetic Code: DNA carries hereditary information (e.g., traits passed from parents).
Homeostasis Definition: The process of maintaining a stable internal environment, like temperature or pH regulation.
Quantitative Observations: Observations involving numbers or measurements (e.g., plant height of 30 cm).
Qualitative Observations: Descriptive observations without measurements (e.g., a leaf is green).
Experimental Setup/Group: The experimental group exposed to a specific variable.
Steps of the Scientific Method (Order): Observation, Question, Hypothesis, Experiment, Data Collection and Analysis, Conclusion, Communication of Results.

Chapter 2: The Chemistry of Life

Element Definition: A pure substance made of one type of atom (examples: O, C, H).
Activation Energy: Energy needed to start a chemical reaction.
Buffer: Substance that maintains stable pH by neutralizing acids or bases.
Acids: Substances with a pH less than 7 (e.g., vinegar).
Bases: Substances with a pH greater than 7 (e.g., soap).
Protein Functions: Catalysing enzymes, structural support, transport, cell communication (hormones).
Amino Acid Definition: Building blocks of proteins.
Carbohydrate Functions: Energy storage (glucose, starch), structural support (plant cellulose).
Nucleic Acid Functions: Store and transfer genetic information (DNA, RNA).
Lipid Functions: Energy storage, insulation, membrane formation.
Solution Definition: A homogeneous mixture (e.g., saltwater).
Solvent Definition: The dissolving substance (e.g., water).
Solute Definition: The dissolved substance (e.g., salt).
Water Molecule: Two hydrogen atoms, one oxygen atom; a polar molecule due to unequal charge distribution.

Chapter 7: Cell Structure and Function

Cell Theory:
- All living things are made of cells.
- Cells are the basic unit of life.
- All cells come from pre-existing cells.
Eukaryotic vs. Prokaryotic Cells: Eukaryotic cells have a nucleus and organelles, prokaryotic cells do not; both have DNA, cell membranes, and cytoplasm.
Organelle Functions:
- Nucleus: Stores DNA.
- Mitochondria: Energy production.
- Chloroplast: Photosynthesis (plants);
- Ribosomes: Protein synthesis.
Hypertonic, Hypotonic, and Isotonic Solutions:
- Hypertonic: Higher solute outside, cell shrinks.
- Hypotonic: Higher solute inside, cell swells.
- Isotonic: Equal concentration, no change.
Diffusion and Osmosis:
- Diffusion: Movement of particles from high to low concentration (no energy).
- Osmosis: Diffusion of water.
Active Transport: Movement of substances against a concentration gradient (energy required).
Hydrophobic: Water-repelling.
Hydrophilic: Water-attracting.

Chapter 23: Plant Structure and Function

Photosynthesis Layer in Leaves: Occurs in the mesophyll.
Stomata Function: -Allow gas exchange (CO₂ in, O₂ out).
- When open-Gas exchange and water loss.
- When closed—Conserves water.
Angiosperm Reproductive Parts:
- Male: Stamen (anther and filament).
- Female: Pistil (stigma, style, ovary).
Seed Dispersal Methods: Wind, water, animals, mechanical ejection.

Chapter 8: Photosynthesis

Photosynthesis Equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
ATP Function: Provides energy for cellular processes.
Photosynthesis Organelle: Chloroplast.
Chlorophyll Function: Captures light energy (reflects green light).
Light Reaction:
- Reactants: Light, water, ADP, NADP⁺.
- Products: Oxygen, ATP, NADPH.
Calvin Cycle:
- Reactants: CO₂, ATP, NADPH.
- Products: Glucose.

Chapter 9: Cellular Respiration and Fermentation

Cellular Respiration Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP)
Organisms: Eukaryotes and some prokaryotes.
Cellular Respiration Organelle: Mitochondria.
Cellular Respiration Stages: Glycolysis, Krebs Cycle, Electron Transport Chain.
Oxygen Requirement: Yes.
Products: ATP, CO₂, H₂O.
Fermentation Types:
- Lactic Acid Fermentation: Produces lactic acid.
- Alcoholic Fermentation: Produces ethanol and CO₂.

Chapter 10: Cell Growth and Division

Interphase Stages:
- G₁: Cell growth.
- S: DNA replication.
- G₂: Preparation for mitosis.
Sister Chromatids and Centromeres:
- Sister Chromatids: Identical chromosome copies.
- Centromere: Region connecting sister chromatids.
Mitosis Stages (Order): Prophase, Metaphase, Anaphase, Telophase.
Spindle Fibers Role: Separate chromosomes.
Cytokinesis: Division of cytoplasm.

Chapter 12: DNA

DNA Structure Discoverers: Watson, Crick, Franklin.
Nucleotide Components: Phosphate, sugar, nitrogenous base (A, T, C, G).
Base Pairing: A-T, C-G.
DNA Replication: Unwinding, base pairing, joining; enzymes include DNA helicase, DNA polymerase and ligase.