Cell Theory & Structure Flashcards
State the six ideas of Cell Theory
Living organisms are made up of cells.
Cells are the basic structural unit of all organisms.
All cells come from pre-existing cells.
Energy flow occurs within cells.
DNA is passed on from cell to cell.
All cells have the same basic cell composition.
What are the characteristics of ‘living things’?
Movement - all move in some way
Respiration - the ability to release energy from food
Sensitivity - detects changes in surrounding environment
Growth - all things grow
Reproduction - Can reproduce and pass genetic info onto offspring
Excretion - Can get rid of waste
Nutrition - intake of nutrients
What is the purpose of the nucleus?
Contains the organism’s genome
Describe the structure of the nucleus
Enclosed in a double membrane and communicates w/ cytosol via nuclear pores
What is the purpose of the nucleolus?
Produces ribosomes, which are critical in protein synthesis
What are the mitochondria?
Membrane-bound organelles that have a double membrane
What is the purpose of the mitochondria?
Provides the energy a cell needs to move, divide, and contract. (Powerhouse of the cell)
What are the names of the folds of the mitochondria?
Cristae
What is the Golgi body?
A stack of membrane-bound vesicles and has a single membrane.
What is the role of the Golgi Body?
Packages macromolecules in vesicles.
What is the Smooth ER?
A network of membrane-bound vesicles and tubules.
What is the function of the Smooth ER?
Lipid and steroid hormone synthesis
Breakdown of lipid-soluble toxins in liver cells
Control of calcium release in muscle cell contraction
What is dotted on the Rough ER and what is their purpose?
Ribosomes, synthesise proteins which are then transported throughout the cell
What is a lysosome?
Type of vesicle
What do lysosomes do?
Little packages that contain enzymes for intracellular digestion (common in animal cells)
What are vacuoles (animal cells)?
A membrane bound-sac that helps to store food or nutrients, sometimes waste products to prevent contamination.
What are vacuoles (plant cells)?
Stores nutrients and waste products
Helps increase cell size during growth
Acts like the lysosome of animal cells
Regulates turgor pressure
Why is turgor pressure important?
It produces rigidity in the plant. Without sufficient water, pressure drops and the plant wilts.
How do we describe the layers of the cell membrane?
Lipid bilayer, composed of phospholipids
How do we describe the nature of the exposed heads?
Hydrophilic=water loving, compatible with water inside cytosol and outside of cell
How do we describe the nature of the tails?
Hydrophobic=water fearing, allows the cell membrane to act as a protective barrier to uncontrolled water flow
What is the purpose of the cytoskeleton?
Cell motility, helps maintain shape of cell and internal movement of organelles
What is the purpose of the cytoskeleton?
Cell motility, helps maintain shape of cell and internal movement of organelles
What are the three filaments of the cytoskeleton?
Microtubules, microfilaments and intermediate fibres
What is the cytoplasm?
Cytosol plus organelles
What is cytosol?
Fluid where cell metabolism occurs, full of proteins
What cells have a cell wall?
Plants
What is the role of the cell wall?
Provides and maintains shape as well as a protective barrier
What cells are chloroplasts found in?
Plants
What is the role of chloroplasts?
Contain chlorophyll (responsible for green colour and to absorb energy from sunlight)
What process occurs in chloroplasts?
Photosynthesis
