B1 Flashcards
What are the two types of cells?
Eukaryotic and Prokaryotic
What are the differences between eukaryotic and prokaryotic cells?
- Prokaryotic cells are smaller
- Eukaryotic cells contain membrane bound-organelles and a nucleus
What is the prokaryotic cell wall composed of?
Peptidoglycan
How is genetic information stored in a prokaryotic cell?
Found free within the cytoplasm as:
- Chromosomal DNA
- Plasmid DNA
What are plasmids?
Small, circular loops of DNA found free in the cytoplasm they carry genes that provide a genetic advantage
What is order of magnitude?
A power to the base 10 used to quantify and compare size
What is a centimetre?
1 x 10-2
What is a millimetre?
1 x10-3
What is a micrometer?
1 x 10-6
What is a nanometre?
1 x10-9
Other than storing genetic information what is the function of the nucleus?
Controls cellular activities
Describe the structure of the cytoplasm
- Fluid component of the cell
- Contains organelles, enzymes and dissolved ions and nutrients.
What is the function of the cytoplasm?
- Site of cellular reactions
- Transport medium
What is the function of the cell membrane?
Controls the entry and exit of materials into and out of the cell
What is the function of mitochondria?
Site of later stages of aerobic respiration
What is the function on ribosomes?
Protein synthesis
What is a plant wall made of?
Cellulose
What is the function of the plant cell wall?
- Provides strength
- Prevents the cell bursting when water enters
What dies the permanent vacuole contain?
Cell sap (a solution of salts, sugars and organic acids)
What is the function of the permanent vacuole?
Supports the cell, maintaining its turgidity
What is the function of chloroplasts?
Site of photosynthesis
Describe how sperm cells in animals are adapted to their function?
- Haploid nucleus: contains genetic information
- Tail: enables movement
- Mitochondria: provide energy for tail movement
- Acrosome: constrains enzymes that digest the egg cell membrane
Describe how nerve cells in animals are adapted to their function?
- Long axon: allows electrical impulses to be transmitted all over the body from the central nervous system
- Dendrites: from the cell body connect to and receive impulses from other nerve cells, muscles and glands
- Myelin sheath: insulates the axon and speeds up the transmission of impulses along the nerve cell
Describe how muscle cells in animals are adapted to their function?
- Arrangement of protein filaments: allows them to slide over each other to produce muscle contraction
- Mitochondria: to provide energy for muscle contraction
- Merged cells in skeletal muscle: allow muscle fibre contraction in unison
Describe how root hair cells in plants are adapted to their function?
- Large surface area: to absorb nutrients and water form surrounding soil
- Thin walls that do not restrict water absorption
Describe how xylem cells in plants are adapted to their function?
- No upper or lower margins between cells: to provide a continuous route for water to flow
- Thick, woolly side walls: strengthen their structure and prevent collapse
Describe how phloem cells in plants are adapted to their function?
- Serve plates: let dissolve amino acids and sugars be transported up and down the stem
- Companion cells: provide energy needed for active transport of substances along the phloem
What is cell differentiation?
The process by which cells become specialised
Why is cell differentiation important?
Allows production of different tissues and organs that perform various vital function in the human body
At what point in their life cycle do most animal cells differentiate?
Early in their life cycle