Cell Structure - Cell Structure Flashcards
Define the term eukaryotic
Eukaryotic means the cell contains a membrane bound nucleus
Define the term prokaryotic
Prokaryotic means that DNA is not found in a nucleus, but is found in the cytoplasm
Identify animal, plant, algal, fungal, bacteria as either eukaryotic or prokaryotic
- Animal cell = Eukaryotic
- Plant cell = Eukaryotic
- Algal cell = Eukaryotic
- Fungal cell = Eukaryotic
- Bacterial cell = Prokaryotic
Describe the structure of the plasma membrane
Made up of phospholipids, proteins and carbohydrates arranged into a fluid mosaic model
Describe the function of the plasma membrane
It controls the passage of molecules in and out of the cell
Describe the structure of the nucleus
- Has a nuclear envelope (double membrane with nuclear pores)
- Contains chromosomes
- Contains a nucleolus
Describe the function of the nucleus
- DNA codes for polypeptides
- Pores allow substances to move between the nucleus and the cytoplasm
- The nucleolus makes ribosomes
- DNA replication occurs here
- mRNA and tRNA are made here
Describe the structure of the mitochondria
- Have an inner membrane which form cristae (folding) and an outer membrane
- Liquid found is called the matrix
Describe the function of the mitochondria
- Sites of aerobic respiration
- ATP is formed here
- Folding increases surface area
Describe the structure of the lysosomes
Sacs surrounded by a single membrane. Produced by the Golgi apparatus.
Describe the function of the lysosomes
Contain digestive enzymes called lysozymes and digest old organelles and cells and foreign molecules
Describe the structure of the ribosomes
- Small structures which are found mostly on the endoplasmic reticulum
- Made from ribosomal RNA and proteins
Describe the function of the ribosomes
Carry out protein synthesis
Describe the structure of the endoplasmic recticulum
- Smooth reticulum contains no ribosomes.
- Rough reticulum contains ribosomes
Describe the function of the endoplasmic recticulum
Smooth reticulum is where lipids are synthesized
Describe the function of the Golgi apparatus
Modifies and packages proteins from the rough ER into vesicles for secretion
Describe the structure of the chloroplasts
Has a double membrane
Describe the function of the hloroplasts
The location for photosynthesis
Describe the structure of the vacuole
- Contains cell sap
- Has a membrane called a tonoplast
Describe the function of the vacuole
Helps to maintain pressure inside the cell and keep it rigid
What are the comparisons between prokaryotic and eukaryotic cells
They both contain cytoplasm and a cell surface membrane
State the equation for magnification
Magnification = image size / actual size
Define the term magnification
How much larger the object appears than its real size
Define the term resolution
The ability to distinguish two objects that are close together, as separate objects
Explain how optical microscopes work
- Specimens are illuminated with light, which is focused using glass lenses and viewed using the eye
- Specimens can be living or dead but often need to be stained with colour dye to make certain organelles visible
What are the limitations of optical microscopes
- Magnification is low, so only large organelles such as the nucleus can be observed
- At higher magnifications, the microscope loses resolution
Explain how electron microscopes work
- Uses a beam of electrons rather than light
- Beam of electrons has a very small wavelength (1nm)
- They
What are the limitations of electron microscopes
Compare optical and electron microscopes
Contrast optical and electron microscopes
Compare a scanning and transmission electron microscopes
Contrast a scanning and transmission electron microscopes
State why pure samples of organelles are needed for study
Describe the process of cell fractionation and ultracentrifugation
Explain why an ice-cold isotonic buffer solution is used
