UPCAT Biology — AnimalsCheat Sheet
Cheat sheet for UPCAT Biology — Animals. Compact, printable, and organised around the concepts University of the Philippines tests most frequently in the UPCAT 2026. Perfect for the week before exam day.
Exam context
On the UPCAT 2026, the Biology subtest carries a "Core" weight in University of the Philippines's pattern. Animals lands at position 4th out of 7 in the standard review order. Target score is UPG ≤ 2.2 typical, and roughly 20 items come from Biology on a typical UPCAT paper.
Animals - Cheat sheet
Your last-minute revision companion for Animals in Biology - covering classification, tissues, development, and cellular processes
Sections
Section Title
Animal Classification
Important Facts
- Invertebrates make up 98% of the animal kingdom
- Cold-blooded animals cannot survive in extreme environments
- Vertebrates have either bony or cartilaginous skeletons
- Warm-blooded animals can survive in various climates
Key Definitions
Term
Invertebrates
Example
98% of animal kingdom - insects, worms, jellyfish
Definition
Animals that lack a vertebral column or backbone
Term
Vertebrates
Example
Fish, birds, mammals, reptiles, amphibians
Definition
Animals with vertebrae or backbone, either bony or cartilaginous
Term
Cold-blooded (Ectothermic)
Example
Fish, reptiles, amphibians
Definition
Animals that cannot regulate internal body temperature
Term
Warm-blooded (Endothermic)
Example
Birds and mammals
Definition
Animals that maintain nearly constant body temperature
Diagrams To Know
- Animal classification tree showing invertebrates vs vertebrates
- Examples of cold-blooded vs warm-blooded animals
Section Title
Animal Tissues
Important Facts
- Four basic types of animal tissue exist
- Skeletal muscle is attached to bone and moves the body
- Smooth muscle is found in organ linings
- Cardiac muscle is found only in the heart
- Connective tissue can be densely or loosely packed
- Blood is considered a fluid connective tissue
Key Definitions
Term
Epithelial Tissue
Example
Skin, mouth lining, digestive system lining
Definition
Layers of tightly packed cells that line body surfaces for protection, secretion, and absorption
Term
Muscle Tissue
Example
Skeletal, smooth, and cardiac muscle
Definition
Cells with contractile filaments that change cell size to produce movement
Term
Nervous Tissue
Example
Brain, spinal cord, peripheral nerves
Definition
Nerve cells (neurons) that form the nervous system
Term
Connective Tissue
Example
Bone, blood, fat, cartilage
Definition
Various cell types involved in body structure and support
Diagrams To Know
- Four types of animal tissues with examples
- Three types of muscle tissue comparison
- Connective tissue types and locations
Section Title
Animal Development Stages
Important Facts
- Development follows specific sequential stages
- Morula is a solid ball of cells
- Blastula is a hollow, fluid-filled ball of cells
- Ectoderm becomes skin and nervous system
- Endoderm becomes gut lining and internal organs
- Mesoderm becomes muscles, bones, and heart
- Cell differentiation occurs when cells express different genes
- Morphogenesis involves cell divisions, migration, and programmed cell death
Key Definitions
Term
Gamete Formation
Example
Ovaries produce eggs, testes produce sperm
Definition
Production of eggs and sperm in specialized tissues (n + n)
Term
Fertilization
Example
Results in diploid zygote
Definition
Fusion of egg and sperm plasma membranes, then nuclei fusion (2n)
Term
Zygote
Example
Single diploid cell that will develop into organism
Definition
First cell of new animal formed after fertilization (2n)
Term
Cleavage
Example
Forms morula then blastula
Definition
Mitotic cell divisions converting zygote to multicellular organism
Term
Gastrulation
Example
Forms ectoderm, endoderm, and mesoderm
Definition
Major cellular reorganization into 2 or 3 tissue layers
Diagrams To Know
- Animal development stages from gamete to gastrula
- Three germ layers and their derivatives
- Cleavage process from zygote to blastula
Section Title
Cellular Transport
Important Facts
- Active transport requires energy (ATP)
- Passive transport occurs naturally without energy
- Concentration gradient determines direction of passive transport
- Semi-permeable membranes allow selective passage
- Endocytosis and exocytosis are types of active transport
- Osmosis specifically involves water movement
Key Definitions
Term
Active Transport
Example
From low to high concentration areas
Definition
Uses ATP to pump molecules against concentration gradient
Term
Passive Transport
Example
From high to low concentration areas
Definition
No energy required; molecules move down concentration gradient
Term
Diffusion
Example
May or may not cross membrane
Definition
Movement of molecules from high to low concentration
Term
Facilitated Diffusion
Example
Ions crossing membrane via channels
Definition
Diffusion through membrane using transport proteins (permeases)
Term
Osmosis
Example
Water moving down concentration gradient
Definition
Diffusion of water through semi-permeable membrane
Term
Endocytosis
Example
Cell membrane surrounds and internalizes particles
Definition
Cell captures substances from outside by engulfing them
Term
Exocytosis
Example
Secretion of hormones or waste products
Definition
Vesicles fuse with cell membrane to release contents outside
Diagrams To Know
- Active vs passive transport comparison
- Endocytosis and exocytosis processes
- Diffusion, facilitated diffusion, and osmosis diagrams
Common Values
Value
46 (23 pairs)
Symbol
2n = 46
Quantity
Human chromosome number
Value
23
Symbol
n = 23
Quantity
Human gamete chromosomes
Section Title
Cell Biology Basics
Important Facts
- Robert Hooke first observed cells in cork
- All cells have DNA, RNA, ribosomes, and cell membrane
- Surface area must be large relative to volume
- Prokaryotic cells are smaller and simpler
- Eukaryotic cells are larger and more complex
- Mitosis has four phases: prophase, metaphase, anaphase, telophase
- Cancer occurs when cell cycle control malfunctions
- Human somatic cells have 46 chromosomes (23 pairs)
Key Definitions
Term
Cell Theory
Example
Fundamental principle of biology
Definition
All life is composed of cells; cells are functional units; all cells come from preexisting cells
Term
Prokaryotic Cells
Example
Bacteria and archaea
Definition
Cells lacking membrane-bound nucleus and organelles
Term
Eukaryotic Cells
Example
Plants, animals, fungi, protists
Definition
Cells with membrane-enclosed nucleus and organelles
Term
Mitosis
Example
Growth and repair in multicellular organisms
Definition
Cell division producing two genetically identical diploid cells
Term
Meiosis
Example
Sexual reproduction in animals
Definition
Cell division producing four genetically different haploid gametes
Diagrams To Know
- Prokaryotic vs eukaryotic cell comparison
- Mitosis phases diagram
- Meiosis process showing chromosome reduction
- Cell organelles and their functions
Must Remember
- Invertebrates make up 98% of the animal kingdom
- Four types of animal tissues: epithelial, muscle, nervous, connective
- Animal development: gamete formation → fertilization → cleavage → gastrulation
- Three germ layers: ectoderm (skin, nervous), endoderm (gut), mesoderm (muscles, bones)
- Active transport uses ATP and moves against concentration gradient
- Passive transport requires no energy and follows concentration gradient
- Prokaryotic cells lack membrane-bound nucleus and organelles
- Eukaryotic cells have membrane-enclosed nucleus and organelles
- Mitosis produces 2 identical diploid cells for growth and repair
- Meiosis produces 4 different haploid gametes for reproduction
Last Minute Tips
- Remember the percentage: 98% invertebrates, 2% vertebrates
- For transport processes, ask: 'Does it need energy?' If yes, it's active transport
- Germ layer memory trick: Ecto = outer (skin), Endo = inner (gut), Meso = middle (muscles)
- Cell division memory: Mitosis = Multiplication (growth), Meiosis = Making gametes
- Muscle tissue types: Skeletal = voluntary, Cardiac = heart only, Smooth = organs
Comparison Tables
Rows
Values
- Smaller
- Larger
Property
Size
Values
- Simpler
- More complex
Property
Complexity
Values
- No membrane-bound nucleus
- Membrane-enclosed nucleus
Property
Nucleus
Values
- Lack membrane-bound organelles
- Have membrane-bound organelles
Property
Organelles
Values
- Bacteria, Archaea
- Plants, Animals, Fungi, Protists
Property
Examples
Columns
- Feature
- Prokaryotic
- Eukaryotic
Table Title
Prokaryotic vs Eukaryotic Cells
Rows
Values
- Yes (ATP)
- No
Property
Energy Required
Values
- Against concentration gradient
- Down concentration gradient
Property
Direction
Values
- Endocytosis, Exocytosis
- Diffusion, Osmosis, Facilitated diffusion
Property
Examples
Values
- Low to high
- High to low
Property
Concentration
Columns
- Feature
- Active Transport
- Passive Transport
Table Title
Active vs Passive Transport
Rows
Values
- Attached to bones
- Voluntary
- Striated
Property
Skeletal
Values
- Heart only
- Involuntary
- Striated
Property
Cardiac
Values
- Organ linings
- Involuntary
- Non-striated
Property
Smooth
Columns
- Type
- Location
- Control
- Appearance
Table Title
Three Types of Muscle Tissue
Rows
Values
- Growth and repair
- Sexual reproduction
Property
Purpose
Values
- One
- Two
Property
Number of divisions
Values
- Two
- Four
Property
Number of daughter cells
Values
- Identical to parent
- Different from parent
Property
Genetic similarity
Values
- Diploid (2n)
- Haploid (n)
Property
Chromosome number
Columns
- Feature
- Mitosis
- Meiosis
Table Title
Mitosis vs Meiosis
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