Cells Flashcards
What did Matthias Schleiden and Theodor Schwann propose in 1883?
That all plants and animals were made up of cells
What did Rudolf Virchow propose in 1855?
New cells could only arise from the division of pre-existing cells and the chemical reactions of life took place within the cell
4 principles of the modern cell theory
All living things are made up of cells
New cells are formed by the division of pre-existing cells
Cells contain genetic material, which is passed on from parent to daughter cells
All metabolic reactions take place inside the cell
Organisms made up of just one cell
Unicellular
Organisms made up of more than one cell
Multicellular
Differences between prokaryotic cells and eukaryotic cells
Prokaryotes do not have a nucleus or membrane bound organelles
Eukaryotes have genetic material in the nucleus whereas prokaryotes have a main chromosome of DNA called a nucleoid and small rings of DNA called plasmids
Examples of eukaryotes
Animals, plants, fungi
Examples of prokaryotes
Bacteria
Differences between plant and animals cells?
Plant cells also have a cellulose cell wall, plasmodesmata, chloroplasts, large permanent vacuoles but they do not have centrioles
Functions of the cell wall
Provide support for the cell by allowing it to become turgid
Provide mechanical strength to the cell
They are freely permeable to water and substances in solution
The cell walls of adjacent cells are glued together by?
Middle lamella, a jelly like substance made up of calcium pectate and magnesium pectate
What membrane is bound by the tonoplast?
The vacuole in plant cells
What does the vacuole of a plant cell contain?
Cell sap which is a solutions of sugars, amino acids, mineral salts and waste chemicals dissolved in water
Functions of the plant vacuole?
Water enters the vacuole by osmosis
Act as stores for foods like sugar and amino acids
Accumulate waste products
Some contain coloured pigment to give the plant colour
What does the nucleus contain?
DNA
What is the nucleus surrounded by?
Nuclear membrane, it is a double membrane with space in between
What is the name of the material inside the nucleus?
Nucleoplasm. It contains chromatin (made up of DNA) attached to proteins called histones
What does the nucleolus make?
rRNA and assembles ribosomes
Functions of the nucleus?
DNA contains genetic information for synthesis of proteins
Genetic material of the nucleus controls metabolism of the cell
Produces new chromosome material at cell division so each daughter cell is genetically identical
Why does haemoglobin not contain a nucleus?
To save space to enable them to carry more oxygen
What are the fluid filled spaces in the endoplasmic reticulum called?
Cisternae
Function of the cisternae?
A system of passages to allow materials to be transported throughout the cell
Rough endoplasmic reticulum contain ……. on its surface?
Ribosomes
Main function of roughy endoplasmic reticulum
To package and transport proteins made by ribosomes
Proteins are transported via the cisternae to vesicles to the Golgi body
RER can also produce pieces of new plasma membrane for the cell
Function of smooth endoplasmic reticulum
Synthesis of lipids and steroids
Transport of material through the cell in vesicles
Where are ribosomes found?
Free in the cytoplasm or on the rough endoplasmic reticulum
Ribosome function?
Protein synthesis
How are Golgi bodies formed?
Small pieces of rough endoplasmic reticulum are pinched off the ends to form small vesicles. These vesicles then join together