DP Biology (first assessment 2025)

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Question 23M.2.SL.TZ2.7a

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Date May 2023 Marks available [Maximum mark: 7] Reference code 23M.2.SL.TZ2.7a
Level SL Paper 2 Time zone TZ2
Command term Describe Question number a Adapted from N/A
a.
[Maximum mark: 7]
23M.2.SL.TZ2.7a
(a)

Describe the organelles and other structures in animal cells that are visible in electron micrographs.

[7]

Markscheme
  1. plasma membrane is thin layer forming outer boundary;
  2. cytoplasm fills space between membrane and nucleus;
  3. nucleus enclosed in nuclear membrane / nuclear membrane enclosing nucleus;
  4. chromosomes inside the nucleus/ visible during mitosis/ as rods (of condensed DNA);
  5. mitochondria with cristae/double membranes;
  6. (80S) ribosomes seen as dots free in cytoplasm/attached to rough ER;
  7. endoplasmic reticulum is a network interconnected tubes/ membranes /rough ER has ribosomes/ smooth ER does not;
  8. Golgi apparatus with stack of sacs/cisternae/curved or folded membranes/vesicles budding off;
  9. vesicles which are small membrane sacs;
  10. lysosome which contains enzymes/which is densely staining;
  11. any other organelle that would be visible correctly described;

Allow any point made on an annotated diagram.

Do not award any marks for just labels. Descriptions are needed.

Syllabus sections