College Entrance Exam Study Guide

COLLEGE ENTRANCE EXAM STUDY GUIDE

Overview

• Key Subjects: Science is included in all major school admission tests (except Ateneo) and includes General Science, Biology, Chemistry, and Physics.

• This module summarizes important concepts, diagrams, and formulas to aid in exam preparation.

Table of Contents

• Biology
    - Living Things
    - Different Types of Cells
    - Organelles
    - Plant Cells vs Animal Cells
    - Cellular Energetics
    - Adenosine Triphosphate (ATP)
    - Sources of ATP
    - Photosynthesis
    - Cellular Respiration
    - Genetics
    - The Molecular Structure of DNA
    - RNA
    - Cell Reproduction
    - The Cell Cycle
    - Mitosis
    - Purpose of Mitosis
    - Haploids vs Diploids
    - Overview of Meiosis
    - Mutations
    - Heredity
    - Gregor Mendel: The Father of Genetics
    - Mendelian Genetics
    - Beyond Mendelian Genetics
    - Sex-Linked Traits
    - Diversity of Organisms
    - Taxonomy
    - How Classification Works
    - Naming Names
    - Nitty Gritty of Classification
    - Symmetry

• Physics
    - Subdivision of Physics
    - Measurements
    - Scalars and Vectors
    - Newton's Laws of Motion
    - Momentum
    - Work
    - Energy

Biology

LIVING THINGS

• Definition: All living things, including plants and animals, are composed of cells.

• Cell Theory: The cell is the basic unit of structure and function in all living organisms.

• Importance: Cell is the smallest unit of living material that carries out all life activities.

• Types of Microscopes:
    - Light Microscope: Used for stained or living cells, magnification up to 1,000 times.
    - Electron Microscope: Detailed study of cell structure, magnifies up to 250,000 times but can only observe killed cells.

WHAT ARE THE DIFFERENT TYPES OF CELLS?

• Eukaryotic Cells: Contain a nucleus and organelles (e.g., fungi, protists, plant cells, animal cells).

• Prokaryotic Cells: Lack a membrane-bound nucleus and organelles, consist of smaller structures; genetic material is circular DNA (e.g., bacteria).

• Components of Prokaryotic Cells:
    - Plasma Membrane
    - Cell Wall (usually made of peptidoglycan)
    - Nucleoid (area containing DNA)
    - Ribosomes (smaller than eukaryotic ribosomes)
    - Flagellum (for movement)

ORGANELLES

• Eukaryotic Cell Structure: Resembles a factory with specialized organelles.

• Plasma Membrane: Semi-permeable, regulates substance movement, consists of phospholipid bilayer.

• Nucleus: Control center, contains DNA, organizes into chromosomes, produces rRNA and ribosomes in the nucleolus.

• Ribosomes: Sites for protein synthesis; may be free or attached to the endoplasmic reticulum (ER).

• Endoplasmic Reticulum (ER):
    - Rough ER: Studded with ribosomes, synthesizes proteins for export.
    - Smooth ER: Lacks ribosomes, synthesizes lipids, hormones, steroids, detoxifies chemicals.

• Golgi Bodies: Process, modify, and package proteins into vesicles for transport.

• Mitochondria: Powerhouses of the cell; convert organic molecules energy into ATP.

• Lysosomes: Contain digestive enzymes; breakdown obsolete organelles and debris.

• Centrioles: Assist during cell division by producing spindle fibers.

• Vacuoles: Store water, food, wastes; large vacuoles found in plant cells.

• Peroxisomes: Detoxify substances; break down hydrogen peroxide.

• Cytoskeleton: Provides structure and shape to the cell using microtubules and microfilaments.

PLANT CELLS VS ANIMAL CELLS

• Unique Structures in Plant Cells:
    - Cell Wall: Rigid outer layer for support.
    - Chloroplasts: Organelles for photosynthesis, containing chlorophyll.
    - Large Central Vacuole: Stores cell sap and maintains pressure.

• Cell Types Summary:
    | Structure | Prokaryotic | Plant Cell | Animal Cell |
    |----------------|-------------|------------|-------------|
    | Cell Wall | Yes | Yes | No |
    | Plasma Membrane| Yes | Yes | Yes |
    | Organelles | No | Yes | Yes |
    | Nucleus | No | Yes | Yes |
    | Centrioles | No | No | Yes |
    | Ribosomes | Yes | Yes | Yes |

CELL METABOLISM

• Definition: Process by which cells convert nutrients into energy.

• Pathways:
    - Catabolism: Breakdown of molecules to generate energy.
    - Anabolism: Synthesis of complex molecules for cellular functions.

CELULAR ENERGETICS

ADENOSINE TRIPHOSPHATE (ATP)

• Energy Currency: Essential for cellular functions, consisting of adenosine and three phosphate groups.

• First Law of Thermodynamics: Energy cannot be created or destroyed.

• Second Law of Thermodynamics: Energy transformations lead to increased disorder (entropy).

• Production of ATP: Via photosynthesis and cellular respiration.

SOURCES OF ATP

1. Photosynthesis: The process by which plants convert solar energy to chemical energy, primarily through chlorophyll in chloroplasts.

2. Cellular Respiration: The biochemical process for energy extraction from organic molecules, e.g., glucose.
      -
      $C_6H_{12}O_6 + 6O_2 <br>ightarrow 6CO_2 + 6H_2O + ATP$
      - Types: Aerobic respiration (with oxygen) and anaerobic respiration (without oxygen).
      - Fermentation: In muscle cells, anaerobic respiration produces lactic acid, leading to muscle fatigue.

PHOTOSYNTHESIS

• Stages:
    1. Light-dependent Reactions: Occur in thylakoids; convert light to chemical energy (ATP, NADPH) and require water.
    2. Light-independent Reactions (Calvin Cycle): Occur in the stroma; use ATP, NADPH, and CO2 to produce glucose.

CELLULAR RESPIRATION

• Overview: ATP production through the breakdown of glucose occurs in the following main processes:
    1. Glycolysis:
       - Occurs in cytosol; splits glucose into two pyruvate molecules, producing ATP and NADH.
    2. Krebs Cycle (Citric Acid Cycle):
       - Occurs in mitochondria; further processes pyruvate to produce electron carriers (NADH, FADH2).
    3. Electron Transport Chain:
       - Occurs in inner mitochondrial membrane; uses NADH and FADH2 to produce ATP via oxidative phosphorylation.

GENETICS

DNA: THE MOLECULAR STRUCTURE

• Structure: Double helix composed of nucleotides (phosphate, sugar, nitrogenous base) with specific base pairing (A-T, G-C) determining genetic information.

• Role: Directs the synthesis of proteins through RNA.
    - Transcription: DNA to RNA (in nucleus).
    - Translation: RNA to proteins (in cytoplasm).

CELL REPRODUCTION

CELL CYCLE

• Phases:
    - Interphase: Growth phase (G1, S, G2) before cell division.
    - Mitosis: Division of nucleus (prophase, metaphase, anaphase, telophase).
        - Cytokinesis: Division of cytoplasm occurs post-mitosis.

• Purpose of Mitosis: Produce two identical daughter cells.

• Mitosis vs Meiosis:
    - Mitosis: Somatic cells, 2 identical daughter cells, diploid.
    - Meiosis: Gametes, 4 non-identical daughter cells, haploid.

HAPLOIDS VS DIPLOIDS

• Diploid (2n): Cells with two sets of chromosomes (e.g., humans = 46).

• Haploid (n): Cells with one set of chromosomes (e.g., gametes = 23).

MEIOSIS

• Purpose: Reduction of chromosome number in gametes (e.g., egg and sperm).

• Stages: Two rounds of division (Meiosis I and Meiosis II with prophase, metaphase, anaphase, and telophase stages).

GREGOR MENDEL

• Contribution: Established foundational principles of genetics through pea plant experiments leading to the laws of inheritance (dominance, segregation, independent assortment).

SAMPLING AND PROBABILITY IN GENETICS

• Punnett Squares: Used to predict offspring genotypes and phenotypes based on parental alleles.

EVOLUTION

NATURAL SELECTION

• Principle: Better adapted organisms survive and reproduce, shifting gene frequencies in populations.

• Darwin’s Contribution: Proposed natural selection as the mechanism of evolution, observing variations and their survival advantages in different environments.

EVIDENCE FOR EVOLUTION

• Fossils: Record of historical changes.

• Biogeography: Distribution correlates with ancestry.

• Embryology: Similarities in early development stages.

• Comparative Anatomy: Homologous and analogous structures.

• Molecular Biology: Genetic similarities confirm evolutionary relationships.

DIVERSITY OF ORGANISMS

• Taxonomy: Classification of organisms based on evolutionary relationships.

• Classification Levels: Kingdom, Phylum, Class, Order, Family, Genus, Species.

PHYSICS

SUBDIVISION OF PHYSICS

1. Newtonian Mechanics: Study of forces.

2. Quantum Mechanics: Behavior of particles.

3. Energy: Dynamics of physical processes.

4. Waves: Energy transfer mechanisms.

5. Electricity and Magnetism: Practical implications.

MEASUREMENTS

• Basic Quantities:
    - Length, Time, Mass.

• Derived Quantities:
    - Force, Volume, Density: $Density = rac{mass}{volume}$.

NEWTON'S LAWS OF MOTION

1. 1st Law: Objects remain at rest or in motion unless acted upon.

2. 2nd Law: Relationship between force, mass, and acceleration $F = ma$.

3. 3rd Law: For every action, there's an equal and opposite reaction.

WORK AND ENERGY

• Work: Force applied over distance.

• Energy: Quantity to perform work.

• Kinetic Energy: Energy of motion, $KE = rac{1}{2} mv^2$.

• Potential Energy: Energy of position, $PE = mgh$.

• Power: Rate of doing work, $Power = rac{Work}{time}$.