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Edexcel IAL Biology 3.2 Organisation in multicellular organisms

Use each level's components and shared function in the definition, then verify whether a named example is a cell, tissue, organ or coordinated organ system.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
AS

Exam points

  • Define tissue as similar cells working together to perform a specific function.
  • Define an organ and organ system through their component tissues or organs and function.
  • Classify plant examples such as xylem, phloem or mesophyll at the tissue level.

3.2—Organisation in multicellular organisms question 1

[Maximum number: 1]

The five stages of cancer are used to describe the size and spread of a cancer in a human body.

The mitotic index of a tissue can be used to determine the stage of cancer.

A higher mitotic index is usually linked to a later stage of cancer.
The mitotic index is calculated using the formula

 Mitotic index = number of cells in mitosis  total number of cells ×100\text { Mitotic index }=\frac{\text { number of cells in mitosis }}{\text { total number of cells }} \times 100

Tests were performed on three patients, P, Q and R, who had cancer.
The table shows the number of cells that were counted in each stage of the cell cycle per mm2\mathrm{mm}^{2} of tissue, taken from the same organ in each patient.

Table for Question 3.2—Organisation in multicellular organisms question 1 — Edexcel A-Level Biology AS

State what is meant by the term tissue.

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