Unit 1 Cell Biology Key Area 1 1

Unit 1: Cell Biology Key Area 1. 1 b: Cell structure/ cell wall in cells National 5 Biology 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 1

National 5 Biology Learning Intentions: KA 1. 1 b By the end of this key area, you should be able to describe cell structure ultrastructure and the functions of each or the organelles Ø Specifically be able to discuss • The role of the cell wall. • The cell wall is made of cellulose in plant cells but of different materials in fungal and bacterial cells. (I will tell you what the cell walls are made of in each but you only need to remember cellulose in plants and just that the other two are different) Ø You should also be able to perform • Numeracy activities on cell size to investigate cell length and breadth. 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 2

Unit 1: Cell Biology Ka 1. 1 a Cell ultrastructure and functions. Lesson 4: Comparison of animal, plant, bacterial and fungal cell wall and Measuring cell length 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 3

Cell walls • • We have already learned that the cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It is tough and can be slightly flexible or rigid. It provides the cell with both structural support and protection. The chemical composition (what it is made of) of the cell wall varies between cell types. Remember animal cells have NO cell wall 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 4

Cell walls in different cells • The chemical composition (what it is made of) of the cell wall varies between cell types. Animal cell NO cell wall Plant cell wall made of cellullose Cellulose Fungal cell wall is made of chitin Bacterial cell wall is made of peptoglycan Peptoglycan Chitin 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 5

Cell walls in different cells • • Note you need to know the plant cell wall is made of cellulose AND that fungal and bacterial cell walls are made of different materials (you don’t need to remember the words chitin and peptoglycan) Animal cell NO cell wall Plant cell wall made of cellulose Cellulose Fungal cell wall is made of chitin Bacterial cell wall is made of peptoglycan Peptoglycan Chitin 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 6

Activity – Measuring cell sizes • Cells cannot be seen without the aid of a microscope. • They are so small that we used units called micrometers (μm) or microns to measure them • There are 1000 microns in 1 millimetre. YOU MUST BE ABLE TO MOVE BETWEEN THESE DIFFERENT UNITS> MAKE SURE YOU PRACTISE CONVERTING ONE TO THE OTHER. 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 7

Measuring cell sizes We can estimate the sizes of cells by knowing the diameter of the field of view. e. g. If the field of view is 2 mm which is 2000μm and there are 8 cells streching from one side to the other, then each cell must be 250μm (2000/8) 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 8

Activity – Measuring cell sizes If a microscope had a magnification of X 100, how big would a cell 0. 09 mm across appear to be? ? Answer: 9 mm

Activity – Measuring cell sizes If the field of view down the microscope is 6 mm, what is the length of each cell? 1 MM

Activity – Measuring cell sizes 2 mm (field of view)/ 5 (no. of cells lengthwise across field of view) = 0. 4 mm 2 mm (field of view)/ 10 (no. of cells up and down in field of view) = 0. 2 mm 0. 4 6/13/2021 0. 2 Mrs Smith - N 5 KA 1. 1 b 11

Activity – Measuring cell sizes This cell is 25 mm in the diagram. What is the actual size of the cell? 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 0. 0625 mm 12

Activity – Measuring cell sizes This cell is 20 mm in the diagram. What is the actual size of the cell? 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 0. 05 mm 13

Activity – Measuring cell sizes ______

Task TYK • Complete questions 1 – 4. Torrance p 5 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 15

Task TYK • Complete questions 1 – 4. Torrance p 5 1. 2. 2. 3. Cells (1) A) Cell membrane, mitochondria, nucleus, ribosome's. (4) B) Cell wall, chloroplasts, large central vacuole (3). Chloroplast for photosynthesis, nucleus for control of cell activities, cell membrane for control of movement of substances onto and out of cell, mitochondrion for aerobic respiration (4). 4. A) 1 millimetre = 1000 micrometers (1) 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 16 4. B) 1 micrometer = 0. 001 millimetres (1).

Quick test 1. How is the cell wall of a plant cell different from that of a yeast cell? 2. Name two cell structures that cannot be seen with a light microscope. 3. What features do yeast and plant cells have in common? 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 17

Answers 1. How is the cell wall of a plant cell different from that of a yeast cell? 1. Plant cell wall is made of cellulose, yeast cell wall is made of chitin. 2. Name two cell structures that cannot be seen with a light microscope. 2. Ribosomes and mitochondria. 3. What features do yeast and plant cells have in common? 3. Cell wall, nucleus, cytoplasm, cell membrane, ribosomes, mitochondria and vacuole. 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 18

National 5 Biology Have you achieved your Learning Intentions: KA 1. 1 b Can you describe cell structure ultrastructure and the functions of each or the organelles Ø Specifically can you discuss • The role of the cell wall. • That the cell wall is made of cellulose in plant cells but of different materials in fungal and bacterial cells. (I will tell you what the cell walls are made of in each but you only need to remember cellulose in plants and just that the other two are different) Ø Can you perform • Numeracy activities on cell size to investigate cell length and breadth. 6/13/2021 Mrs Smith - N 5 KA 1. 1 b 19