Summary Grade 9_Natural Sciences Summaries - Noteset

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Natural Science
GRADE 9




1 Grade 9 Natural Sciences I © 2026 Noted™ www.notedsummaries.co.za

, BIOLOGY Cells are the smallest structural and functional units

THE CELL of all living organisms = MICRO-SCOPIC

EUKARYOTIC VS PROKARYOTIC
Animal cell
Type of cell Core? Examples
EUKARYOTIC Eukaryotic

Prokaryotic
True core (core membrane) plants, animals,
fungi
Bacteria
no true nucleus (DNA is not
enclosed in a nucleus)


Mitochondria
Nucleolus
Nucleus PLANT CELL EUKARYOTIC
Mitochondria
MEMBRANE Chloroplast
Nucleolus Ribosomes
Endoplasmic Nucleus
Cytoplasm reticulum Endoplasmic
LYSOSOMES reticulum vacuole
✘vacuole
centriole cell membrane Membrane
✘ Cell wall VARIABLE SHAPE Cytoplasm cell membrane
2 Grade 9 Natural Sciences I © 2026 Noted™ www.notedsummaries.co.za
Cell wall (cellulose)

,STRUCTURES & PLANT CELL ANIMAL
ORGANELLES
Structure / Organelles Where? Function Plant Cell
CELL
Animal Cell
Cell membrane (plasma Plant & animal Semi-permeable ; controls what Cell wall
membrane) enters and leaves the cell Yes (cellulose) No
Cell wall (cellulose) Plant only Strong outer layer; protection and Shape More rigid / rectangular More round / irregular
fixed shape; support Chloroplasts Yes (photosynthesis) No
Cytoplasm (cytosol + Plant & animal Jelly-like medium; holds organelles; Vacuole
organelles) site of many reactions Large central vacuole Small vacuole or
Endoplasmic reticulum Plant & animal Membrane network: Rough ER makes (turgor/support) sometimes none
(ER) proteins; Smooth ER makes lipids Plasmodesmata Yes No
Ribosomes Plant & animal Protein synthesis; free in cytoplasm Lysosomes Rare (vacuole breaks down)
or attached to rough ER Common
Golgi complex Plant & animal Modifies, packages and transports Centrioles Usually absent Typical
proteins and lipids Energy storage Starch Glycogen
Mitochondria Plant & animal Cellular respiration; produces ATP Cytokinesis (cell Cell plate forms Cleavage furrow
(energy)+ O2. division)
Nucleus Eukaryotic cells Control centre; contains DNA
(genetic information) Size (general) Often larger Often smaller


PLANT CELL
Nuclear membrane Plant & animal Surrounds nucleus; separates
nucleus from cytoplasm
Nucleolus Plant & animal Produces ribosomal subunits (rRNA)
Nuclear pores Plant & animal Small openings; allow substances in
and out of nucleus Cell type Function Where found
Vacuole

Chloroplasts
Plant & animal Storage of water and substances;
(size differs)
Plant only
large in plants for turgor/support
Photosynthesis; contains chlorophyll;
makes glucose
Parenchyma


Collenchyma
TYPES General cell= Photosynthesis; Leaves, stems,
storage of food and water roots

Flexible support (can grow with Young stems and
Plastids (e.g. Plant only Storage or production of substances plant) leaf stalks
amyloplast) (e.g. starch)
Plasmodesmata Plant only Channels in cell walls; communication
between cells Sclerenchyma Strong, rigid support (thick cell Hard parts: seeds,
Lysosomes Mostly animal Enzyme sacs that digest large walls) nuts, vessels
molecules plants
( = vacuole)
Centrioles Mostly animal Organise spindle fibresduring cell Xylem cells Transport water and minerals From roots to
division (tracheids & vessels) upward leaves
Cilia / flagella Some animal Movement of cell or surrounding Phloem sieve tubes Transport sugars and Throughout the
cells fluid nutrients plant
3 Grade 9 Natural Sciences I © 2026 Noted™ www.notedsummaries.co.za

, ORGANELLES Cell wall
NUCLEUS
Function : Protection + support
+ fixed form (from cellulose) CHLOROPLAST
MEMBRANE Core Plant cell only
⊗ Function : Photosynthesis
Nucleolus CELLusing CHLOROPHYLL
(making food )

DNA ⊗ Containschlorophyll(green
pigment)= absorbs sunlight energy
⊗ Photosynthesis : carbon dioxide + water
PLASMA + sunlight→ glucose + oxygen
PORE MITOCHONDRIA
⊗ Function : Controls processes and
chemical reactionsin the cell( + contains ⊗ Function : Releasesenergyduring cellular
genetic information) respiration
⊗ Has adouble membrane
Consists of: ⊗ Active cells (e.g., muscle cells) have more
⊗ Nuclearmembrane (double membrane) mitochondria
with pores→ substances moving in/out ⊗ Respiration: food(glucose)+ oxygen→
⊗ Nucleolus→ dark structure in nucleus energy + CO2 + water + wastes
⊗ DNA (genetic information) → hereditary DNA INNER MEMBRANE
traits; differences in DNA = variation Cristae (folds)
Tonoplast vacuole
⊗ Function : Store water/ions +keep cellfirm
⊗ Liquid =cell sap
Cell sap ⊗ Full vacuole→ turgid (firm)
⊗ Empty/smaller vacuole → flaccid (limp)
Ribosomes OUTER
MEMBRANE
4 Grade 9 Natural Sciences I © 2026 Noted™ www.notedsummaries.co.za