Nat 5 - Cell Biology Flashcards
What is the function of the cell wall?
To support the cell
What is the function of the mitochondria?
Site of aerobic respiration
What is the function of the chloroplast?
Site of photosynthesis
What is the function of the cell membrane?
Controls what substances pass into and out of the cell
What is the function of the cytoplasm?
Site of most chemical reactions
What is the function of the vacuole?
Contains cell sap and regulates water content by osmosis
What is the function of the nucleus?
Controls cell activities
What is the function of the ribosome?
Site of protein synthesis
What is the function of the plasmid?
Controls cell activities in bacterial cells
Name the two components of the cell membrane
Proteins and phospholipids
Define the term passive transport
Transport that does not require energy e.g. Diffusion and osmosis
Define the term diffusion
The movement of molecules from an area of a high concentration to an area of a low concentration down a concentration gradient until evenly spread
Name the membrane protein involved in diffusion
Protein channel
Name three raw materials that would diffuse into cells
Oxygen, glucose and amino acids
Name one waste product that would diffuse out of cells
Carbon dioxide
State the importance of diffusion in living cells
It is the process by which useful molecules enter and waste products are removed
Define the term osmosis
The movement of water molecules from a high water concentration to a low water concentration across a selectively permeable membrane
Name the membrane protein involved in osmosis
Protein channel
Describe what happens to an animal cell in pure water
Water moves in from a HWC to a LWC and the cell swells and bursts
Describe what happens to an animal cell in a strong salt solution
Water moves out from a HWC to a LWC and the cell shrinks
Describe what happens to a plant cell in pure water
Water moves in from a HWC to a LWC and the cell becomes turgid
Describe what happens to a plant cell in a strong salt solution
Water moves out from a HWC to a LWC and the cell becomes plasmolysed
Define the term active transport
The movement of ions or molecules from a low concentration to a high concentration against a concentration gradient
Name the membrane protein involved in active transport
Protein pump
Describe the importance of mitosis
It is essential for growth and repair
Define the term diploid
Containing two sets of chromosomes
Describe stage one of mitosis
Chromosomes in the nucleus become visible
Describe stage two of mitosis
Chromosomes replicate to become two identical chromatids
Describe stage three of mitosis
Chromosomes line up along the equator of the cell
Describe stage four of mitosis
Spindle fibres pull chromatids to opposite poles of the cells
Describe stage five of mitosis
Two new nuclei form and cytoplasm splits
Describe stage six of mitosis
Two daughter cells are formed, identical to mother cells
Define the term chromatid
Each of the two thread-like strands which a chromosome divides into during mitosis
Define the term equator
The line across the centre of the cell
Describe the role of the spindle fibres
They pull chromatids to opposite poles of the cell
Explain how mitosis maintains the diploid chromosomes complement
The number of chromosomes in the nucleus are doubled and then divided between the nuclei of the two daughter cells produced. This ensures that the diploid chromosome complement is maintained
Explain why aseptic technique must be used when culturing cells
To prevent contamination from unwanted bacteria and micro organisms
Name two types of growth medium
Nutrient agar and liquid broth
Name three factors that must be controlled when culturing cells
Temperature, oxygen concentration and pH
State what molecule DNA codes for
Proteins
Describe the structure of a DNA molecule
DNA molecules consist of two strands twisted together to form a spiral known as a double helix. Each strand is made up of many smaller units called nucleotides. They also have complementary base pairs.