What is the definition of nutrition and structures in Science?

Question

There's a follow-up question after this: What is the comparison and contrast between the structures, nutrition and reproduction of the 5 kingdoms ( Monera, Protoctista, Fungi, Animalia, Plantae)?

Please reply A.S.A.P. Thanks for helping.

Answer 1

The five-kingdom classification of organisms

Nomenclature: Naming of organisms

Binomial: Biological name of an organism → Genus species

Taxon: Set of organisms within a category / Taxonomy / Study of biological classification

Different levels of taxons: SPECIES, GENUS, FAMILY, ORDER, CLASS, PHYLUM, KINGDOM

Most number of species on right

Most similar organisms on left

Unicellular: Single cell; Colonial: Groups of cells; Multicellular: Many cells

Autotrophs produce energy from inorganic sources

Phototrophs from photosynthesis/sunlight

Chemotrophs from simple inorganic (oxidative) processes

Heterotrophs digest and absorb organic molecules



Prokaryotae (prokaryotes)

Cell structure:

Prokaryotes, unicellular

Prokaryotes lack cytoplasmic organelles found in eukaryotes

Cell wall: murein

Nutrition: autotrophic (photosynthesis, chemosynthesis), aerobic heterotrophs

Divide by binary fission, not by mitosis

≈10μm in size (bacterial cell, filaments of blue-green bacteria)

Mutualistic nitrogen-fixing bacteria live in nodules on the root of legumes / symbiotic



Protoctista (protoctists)

Cell structure: eukaryotes, unicellular and multicellular

Cell wall: (sometimes) polysaccharide

Nutrition: autotrophic, heterotrophic

Placed in this category by exclusion / cannot be placed in any other kingdom

Slime moulds / fungi characteristics

Protozoa / heterotrophic and ingest food

Algae / photosynthesis

≈10μm (amoeba) - 1m (Laminaria / large brown alga)



Fungi

Cell structure: eukaryotes, multicellular and unicellular (yeast)

Cell wall: chitin

Nutrition: heterotrophic / saprotrophic decomposers or parasitic

Genus Penicillium

Body of a fungus is composed of thin filaments called hyphae / form a mycelium

Secret enzymes / external digestion / absorbs resulting nutrients

Erect hyphae that grow upwards from the mycelium carry their reproductive spores

Chains of spores on the erect hyphae / coloured mould visible on stored food

Break down organic matter



Plantae (plants)

Cell structure: only multicellular, eukaryotic; large vacuoles

Cell wall: cellulose

Nutrition: autotrophic (photosynthetic)

Growth is restricted to meristems (layers/patches of dividing cells)

Non-motile; adapted to land / strong tissues, leave gas exchange system, waterproofed

Eg mosses, ferns, conifers, angiosperms (flowering plants)



Plant kingdom has two different types of adults in their life cycle

Gametophytes, hidden in plant / sexual reproduction forms multicellular zygotes

Sporophytes, what we call plant / asexual reproduction to form spores that germinate into gametophytes

Gametophyte (n) → gamete (n) → fertilisation → zygote (2n) → mitosis → sporophyte (2n) → meiosis → spore (n) → mitosis → gametophyte (n)



Animalia (humans, animals)

Cell structure: eukaryotic, multicellular, no cell wall

Develop form a blastocyst / embryo

Have nervous and hormonal control systems

No cell wall!

Nutrition: heterotrophic, involving a digestive system

Are motile and grow throughout tissues (no mersitems)