Biologia Ceallan GCSE - Structar Ceallan

Basic Unit of Life: Cells are the smallest units of living organisms.
Types of Cells:
- Prokaryotic: Simple cells without a nucleus (e.g., bacteria).
- Eukaryotic: Complex cells with a nucleus (e.g., plant and animal cells).
Common Organelles in Eukaryotic Cells:
- Nucleus: Contains genetic material (DNA).
- Cytoplasm: Jelly-like substance where organelles are suspended; site of chemical reactions.
- Cell Membrane: Semi-permeable barrier that controls entry and exit of substances.
- Mitochondria: Powerhouse of the cell; site of aerobic respiration.
- Ribosomes: Sites of protein synthesis.
- Endoplasmic Reticulum (ER):
  - Rough ER: Studded with ribosomes; synthesizes proteins.
  - Smooth ER: No ribosomes; synthesizes lipids.
- Golgi Apparatus: Modifies, sorts, and packages proteins for secretion or use in the cell.
- Chloroplasts (in plant cells): Site of photosynthesis; contain chlorophyll.
- Cell Wall (in plant cells): Provides structure and support; made of cellulose.
Differences Between Plant and Animal Cells:
- Plant cells have a cell wall, chloroplasts, and large central vacuoles.
- Animal cells have lysosomes and smaller vacuoles.

Process of Cell Division: Essential for growth, repair, and reproduction.
Types of Cell Division:
- Mitosis:
  - Purpose: Growth, tissue repair, and asexual reproduction.
  - Phases:
    1. Prophase: Chromosomes condense; nuclear envelope breaks down.
    2. Metaphase: Chromosomes align at the cell’s equator.
    3. Anaphase: Sister chromatids are pulled apart to opposite poles.
    4. Telophase: Nuclear envelope reforms; chromosomes de-condense.
    5. Cytokinesis: Division of the cytoplasm, resulting in two daughter cells.
- Meiosis:
  - Purpose: Produces gametes (sperm and eggs) for sexual reproduction.
  - Phases:
    1. Meiosis I: Homologous chromosomes separate; results in two haploid cells.
    2. Meiosis II: Similar to mitosis; sister chromatids separate, resulting in four haploid gametes.
Importance of Cell Division:
- Maintains genetic continuity.
- Essential for growth, development, and repair of tissues.
- Genetic variation is introduced through meiosis, contributing to evolution.

Aonad Bunait de Beatha: Tha ceallan mar na h-aonadan as lugha de organisman beò.
Seòrsaichean Cealla:
- Procarióta: Ceallan sìmplidh gun nucleus (mar eisimpleir, bacteria).
- Eucarióta: Ceallan matha le nucleus (mar eisimpleir, ceallan plandaichean agus beathaichean).
Organelle coitcheann ann an Ceallan Eucarióta:
- Nucleus: Tha ann a’ cumail a’ mhargaidh ginealaiche (DNA).
- Cytoplasm: Substaint gelly mar a tha organelles ann; àite freagairtean ceimigeach.
- Fiodh Cealla: Barrachd semi-permeable a chùmhnadh air a’ mhodh a’ phuinge.
- Mitochondria: Cinnidh na cealla; àite airson anail de aerobic.
- Ribosomes: Àite airson sintéis pròtain.
- Endoplasmic Reticulum (ER):
  - Rough ER: Le ribosomes; tha e a’ dèanamh pròtain.
  - Smooth ER: Gun ribosomes; tha e a’ dhèanamh lipids.
- Golgi Apparatus: Atharrachadh, cruinneachadh, agus pacadh pròtain airson leigeil a-mach no a chleachdadh anns a’ chealla.
- Chloroplasts (ann am pocketan): Àite airson fotofhoisinteis; tha clorofill ann.
- Ball Cealla (ann am pocketan): A’ toirt structar agus taic; air a dhèanamh le cellulose.
Diofar eadar Ceallan Plandaichean agus Beathaichean:
- Tha ceallan plandaichean a’ toirt a-steach ball cealla, chloroplasts, agus vacuoles mòra meadhanach.
- Tha ceallan beathaichean a’ toirt a-steach lysosomes agus vacuoles nas lugha.

Pròiseas Roinn na Cealla: Tha e riatanach airson fàs, deasg, agus toradh.
Seòrsaichean Roinn na Cealla:
- Mitosis:
  - Adhart: Fàs, deasg, agus toradh a-mhàin.
  - Freagairtean:
    - Prophase: Tha cromosòmaichean a’ comharrachadh; tha an envelope nuclear a’ briseadh.
    - Metaphase: Tha cromosòmaichean a’ fastadh air an equator a’ chealla.
    - Anaphase: Tha chromatids phiuthar air an tarraing a-mach gu polar air an taobh.
    - Telophase: Tha an envelope nuclear a’ cruthachadh; tha cromosòmaichean a’ seargadh.
    - Cytokinesis: Roinn an cytoplasm, a’ nochdadh dà chealla nighean.
- Meiosis:
  - Adhart: A’ dèanamh gametes (sperm agus uighean) airson toradh sexual.
  - Freagairtean:
    - Meiosis I: Tha cromosòmaichean homologous air an rùsgadh; tha e a’ leantainn gu dà chealla haploid.
    - Meiosis II: Coltach ri mitosis; tha chromatid phiuthar air an tarraing a-mach, a’ toirt seachad ceithir gametes haploid.
Cuibhreann Roinn na Cealla:
- A’ cumail leantainneachd ginealach.
- Riatanach airson fàs, leasachadh, agus càradh tissues.
- A’ toirt a-steach atharrachadh ginealaichte tro meiosis, a’ cur gu adhartas.