Cell Theory Flashcards
(28 cards)
Properties of a light microscope
x1000 zoom
Subject can be living
Electron microscope properties
x50 000 000 zoom
Image displayed on monitor
Cannot see colour images and only view dead cells
Confocal laser scanning microscope properties
Lasers build up the image on screen
Lower magnification than electron, clearer than light
Bacteria facts:
Cytoplasm, cell membrane and cell wall
No obvious nucleus - ring of DNA called a plasmid
Produce asexually by dividing in half
Fungi facts
Larger than bacteria
Nucleus, cytoplasm, cell membrane, cell wall
Reproduce asexually by budding
Virus facts:
Smaller than bacteria
Protein coat and genes
Only reproduce inside a host cell
Algae facts:
Cell wall, cell membrane, nucleus and cytoplasm
Photosynthetic because of chloroplasts
What are enzymes?
Biological catalysts that control reactions
How is an enzyme made?
A chain of amino acids fold to form a specific shape. The active site is where the enzyme affects the reaction
Two factors that affect enzyme efficiency?
pH
Temperature
Name three enzymes in washing powder and what they do
Lipase breaks down grease
Protease breaks down amino acids
Carbohydrate breaks down starch
How does the nucleus control the cell?
The arrangement of bases in DNA into triplet codes codes for different amino acid productions and therefore proteins and furthermore enzymes. Enzymes control the chemical reactions in the cell
What are the four bases
Adenine
Thymine
Cytosine
Guanine
Name the four scientists responsible for the discovery of the DNA structure
Francis Crick
Rosalind Franklin
James Watson
Maurice Wilkins
Describe mitosis
Cell division producing two identical diploid cells. Mitosis is growth and repair
Describe meiosis
Produces four genetically different haploid cells (gametes) for use in reproduction.
Where are stem cells found in plants and animals
Meristems Embryos Bone marrow Umbilical cord Deciduous teeth
Define unicellular and multicellular
Unicellular - single celled
Multicellular - many cells
Why are virus’ sometimes considered to not be alive?
They can only reproduce inside a host cell. For something to be considered alive it must be able to reproduce.
How is the active site of an enzyme held in shape?
Chemical bonds
What is the link between enzyme activity and molecular collisions?
Molecules move faster in higher temperatures so there is greater enzyme activity at higher temperatures up to the point where an enzyme denatures
Describe the backbone of DNA
A sugar phosphate backbone that uses hydrogen bonds to hold the bases in place
Which bases are complimentary?
Adenine with thymine
Cytosine with guanine
What is the purpose of mitosis
Growth and repair
