Topic B1 - Cell Biology Flashcards
What is the Nucleus?
Contains genetic material
What is Cytoplasm?
Where most of the chemical reactions happen
What are Ribosomes for?
Where proteins are made
What does Cell Membrane do?
Controls what goes in and out of cell
What is Mitochondria for?
Where most of the reactions for aerobic respiration takes place
What are Chloroplasts?
Where photosynthesis occurs
What is the Permanent Vacuole?
Contains cell sap
What is the Cell Wall?
Made of cellulose - Strengthens the cell
What does a PLANT CELL contain that an ANIMAL CELL doesn’t
1) Chloroplasts
2) Permanent Vacuole
3) Cell Wall
Animal Cell Structure
- Nucleus
- Cytoplasm
- Mitochondria
- Cell Membrane
- Ribosomes
Plant Cell Structure
- Nucleus
- Cytoplasm
- Mitochondria
- Cell Membrane
- Ribosomes
- Cell Wall
- Chloroplasts
- Permanent Vacuole
Prokaryotic Cell Structure
- Cell Wall
- Cell Membrane
- Plasmid (small ring of DNA)
- DNA loop (floating in cytoplasm)
Prokaryotes don’t have a nucleus
What are examples of Eukaryotic Cells?
- Animal Cell
- Plant Cell
What are examples of Prokaryotic Cells?
- Bacterial Cell
What are chromosomes?
Coiled up lengths of DNA molecules, which carry genes.
Found in nucleus
Normally in pairs in body cells
What is the Cell Cycle?
Series of stages in which cells divide to produce new cells
What 3 things does a cell do before it divides?
1) Grows in size
2) Increases the amount of subcellular structures e.g mitochondria, ribosomes
3) Duplicates its DNA
What is Mitosis?
The stage of the cell cycle when the cell divides.
Mitosis Pathway?
1) Cells DNA doubles
- parent cell, two copies of each chromosome
2) Cytoplasm and cell membranes divide
3) Two cells are formed, which are identical to each other and to the parent cell.
Mitosis allows multicellular organisms to grow or replace cells that have been damaged
Cell differentiation definition
The process by which a cell changes to becom specialised for its job
What are 5 examples of specialised cells?
- Sperm Cell
- Muscle Cell
- Nerve Cell
- Xylem and Phloem
- Root Hair Cells
How is a Sperm Cell specialised?
Long tail and streamlined head for swimming to the egg
How is a Nerve Cell specialised?
Long to cover a large distance, and branched to form a network of connections
How is Xylem and Phloem specialised?
Xylem cells are hollow and phloem cells have few subcellular structures, so substances can easily flow through
How are Muscle Cells specialised?
Long so they have space to contract, and lots of mitochondria for energy.
How are Root Hair Cells specialised?
Large surface area for absorbing water and mineral ions from the soil
Stem Cells definition
Undifferentiated cells, which can divide to produce lots more stem cells, can differentiate into many other types of cells.
What can stem cells from adult bone marrow become?
Many kinds of cells, e.g blood cells
What can stem cells from human embryo become?
Any kind of human cell
What can stem cells from plant meristem become?
Any kind of plant cell
What are stem cell uses in medicine?
Stem cells could produce nerve cells to treat paralysis, or insulin-producing cells to treat diabetes.
What are stem cell uses in plants?
Produces clones of whole plants quickly and cheaply
What is an example of a cell with a large SA : Volume ratio?
Single-celled organism
What is an example of a cell with a small SA : Volume ratio?
Multicellular organism
Large SA : Volume ratio benefit
More efficient diffusion of nutrients, or oxygen and carbon dioxide
Small SA : Volume ratio negative
Cells too far from outer surface to get substances in and out
Why are exchange surfaces and transport systems needed?
Needed so the needs of every cell can be met
What 4 things do exchange surfaces usually have?
1) Large surface area
(so lots can diffuse at once)
2) A thin membrane
(for a short diffusion distance)
3) An efficient blood supply
4) Ventilation
(gas exchange in animals);
What are 4 organs adapted for exhange?
1) Leaves
- gas exchange
2) Gills
- gas exchange in fish
3) Small Intestine
- absorption of food molecules from gut to blood
4) Alveoli
- gas exhange in lungs
