Chapter 1 Cells Flashcards
State the function of the mitochondria. [1] (2016/A5)
Site for aerobic respiration whereby glucose is oxidised in the presence of oxygen to release energy for cellular activities.
State three ways in which the structure of a plant cell differs from the animal cell [3] (2016/A5)
(Fig. in qn does not have centrioles)
A plant cell has a cell wall but the animal cell does not have. [1]
A plant cell has chloroplasts but the animal cell does not have. [1]
A plant cell has a large central vacuole but the animal cell has numerous small vacuoles. [1]
Which structures in cells are only visible under an electronic microscope? [6+] (Self)
Basically everything else other than cell membrane & wall, cytoplasm, chloroplasts and nucleus.
Mitochondria, ribosomes, RER, SER, Golgi Apparatus and vesicles.
Nucleus parts are also only visible under electron microscope
What does the nucleus contain? [4] (self)
Nuclear Envelope, neucleoplasm, nucleolus (protein making), chromatin threads
State the structure and function of the RER (self)
Consists of a network of flattened spaces lined with a membrane that is continuous to the nuclear envelope. Its surface appears rough under an electron microscope.
Ribosomes on the surface of the RER make up the rough appearance. They synthesise proteins that are to be transported out of the cell.
State the function of free ribosomes (self)
Synthesise proteins to be used within the cytoplasm of the cell
State the structure and function of the SER (self)
More tubular in shape compared to the RER, and is connected to the RER.
It synthesises substances such as fats and steroids. It also converts harmful substances into harmless materials through a process known as detoxification.
State the structure and function of the Golgi Apparatus. (Self)
The Golgi Apparatus is shaped like a disc. It consists of flattened spaces surrounded by membranes.
It chemically modifies substances prosecuted by the ER and stores and packages these substances in vesicles for secretion outside the cell.
Define differentiation (self)
Differentiation is the process by which a cell becomes specialised for a specific function
Explain how the red blood cell is adapted for its function [3] (self)
- It contains haemoglobin which binds to oxygen, enabling it to transport oxygen around the body.
- It has a circular biconcave shape. This increases its surface to volume ratio, allowing oxygen to diffuse in and out of the cell at a faster rate.
- It lacks a nucleus. This enables the cells to store more haemoglobin to carry more oxygen per blood cell.
State and explain how the xylem vessels are adapted to their function [4] (self)
- Xylem vessels are long hollow tubes extending from the roots to the leaves.
- They are narrow and have no cross walls to obstruct water flow through the lumen.
- They do not have protoplasm offer resistance to water flow.
- Their walls a thickened with lignin to prevent collapse of the vessel
What is a simple tissue? Give examples. (Self)
Cells of the same kind group together to form a simple tissue
E.g. muscular, skin tissue, plant epidermis and mesophyll tissue
What is a complex tissue? Give examples.
A group of more than 1 type if cell.
E.g. blood, xylem, phloem
What is an organ? Give examples. (Self)
An organ contains one or more tissues all working together for a specific function.
E.g. stomach (gland, muscular and nervous tissue) and leaf ( mesophyll, xylem and phleom tissue.
What is an organ system? Give examples.
An organ system consists of several organs working together for a common purpose.
E.g. digestive system, respiratory system, root system and shoot system.
