Chapter 2 - Organisation of the organism Flashcards
What do animal cells contain?
Animal cells have a nucleus, cell membrane, mitochondria, ribosomes, cytoplasm and they store carbohydrates as glycogen.
What do plant cells contain?
Plant cells have a nucleus, cell membrane, mitochondria, ribosomes on rough endoplasmic reticulum, cytoplasm, cell well made from cellulose, chloroplast, a permanent vacuole and they store carbohydrates as starch or sucrose.
What is the function of the nucleus?
Contains the DNA (genetic material) which controls the activities of the cell.
What is the function of the cytoplasm?
A gel-like substance composed of water and dissolved solutes.
Supports the internal structures of the cell.
Site of many chemical reactions including anaerobic respiration.
What is the function of the cell membrane?
Holds the cell together separating the inside of the cell from the outside.
Controls which substances enter or leave the cell.
What is the function of the ribosomes?
Found in the cytoplasm.
The site of protein synthesis.
What is the function of the permanent vacuole?
Contains cell sap which is a solution of sugar and salt.
Used for the storage of certain materials.
Helps to support the shape of the cell.
What is the function of the mitochondria?
The site of aerobic respiration.
What is the function of the cell wall?
Made of cellulose which is a polymer of glucose.
Gives the cell extra support, defining its shape.
What is the function of the chloroplast?
Contains the green chlorophyll pigment that absorbs light energy for photosynthesis.
What do bacteria cells contain?
Bacteria cells are microscopic single-celled organisms. They have a cell wall made of peptidoglycan, cell membrane, cytoplasm, ribosomes, circular chromosome of DNA that floats in the cytoplasm and sometimes plasmids which are small rings of DNA that contains extra genes. Some bacteria also have a flagellum which are long, thin, whip like tails to allow movement.
How are new cells produced?
New cells are produced by the division of existing cells.
What are specialised cells?
Specialised cells have developed certain characteristics in order to perform particular functions.
What are ciliated cells?
Ciliated cells are adapted for movement of mucus in the trachea and bronchi. They have extensions of the cytoplasm at the surface of the cell which form hairlike structures called cilia which beat to move mucus and trapped particles up to the throat.
What are root hair cells?
Root hair cells are adapted for the absorption of water and mineral ions from the soil. The root hair increases surface area of cell to ensure maximum absorption of water and mineral ions. Walls are thin to ensure water moves through quickly. No chloroplasts are present.
What are palisade mesophyll cells?
Palisade mesophyll cells are adapted for photosynthesis. They are column shaped to maximise absorption of sunlight and fit as many in a layer under the upper epidermis of the leaf as possible. Contains many chloroplasts for maximum photosynthesis.
What are nerve cells?
Nerve cells are adapted for the conduction of impulses. They are long so that nerves can run to and from different parts of the body to the central nervous system. The cell has extensions and branches so that it can communicate with other nerve cells, muscles and glands. The axon which is an extension of cytoplasm away from the cell body is covered with a fatty sheath which insulates the nerve cell and speeds up nerve impulses.
What are red blood cells?
Red blood cells are adapted to transport oxygen. They have a biconcave disc shape to increase surface area for more efficient diffusion of oxygen. They contain haemoglobin which joins with oxygen to transport it. They contain no nucleus to increase amount of space available for haemoglobin inside of the cell.
What are sperm cells?
Sperm cells are adapted for reproduction. The head contains the genetic material for fertilisation in a haploid nucleus which contains half the number of chromosomes. The acrosome in the head contains digestive enzymes so that a sperm can penetrate an egg. The mid piece is packed with mitochondria to release energy needed to swim and fertilise the egg. The tail enables the sperm to swim towards the egg.
What are egg cells?
Egg cells are adapted for reproduction. They contain a lot of cytoplasm which has nutrients for the growth of the early embryo. It has a haploid nucleus which contains the genetic material for fertilisation and half the number of chromosomes. The cell membrane changes after fertilisation to form an impermeable membrane by a single sperm so that no more sperm can enter.
Examples of organs and tissues in different organ systems
What is the formula for magnification?
Magnification = image size / actual size
Image size = actual size x magnification
Actual size = image size / magnification
Magnification has no units just ‘x25’ for example.
