S1) Basic Cell Structure Flashcards
State the structure and function of the following:
- Nucleus
- Nucleolus
- Nuclear membrane
- Nucleus – cell’s control centre, contains chromatin and DNA
- Nucleolus – the region at the centre of the nucleus; role in ribosome production (stains dark)
- Nuclear membrane – a two-layered selectively-permeable membrane with pores for passage of substances
State the structure and function of the following:
- Microtubules
- Centriole
- Microvillii
- Microtubules – part of the cell’s cytoskeleton, aid movement of substances through cytoplasm
- Centriole – composed of two cylinders of tubules; essential to cell reproduction
- Microvilli – projections which increase the cell’s surface area
State the structure and function of the following:
- Microfilament
- Vacuole
- Cytoskeleton
- Microfilament – provides support for the cell; sometimes linked to cell’s outer membrane
- Vacuole – sac that stores and transport ingested materials, waste products and water
- Cytoskeleton – internal framework of the cell, made up of microfilaments and hollow microtubules
State the structure and function of the following:
- Cytoplasm
- Ribosome
- Cell membrane
- Cytoplasm –fluid in which organelles float; primarily water, contains enzymes and amino acids
- Ribosome – tiny structure that assists with protein assembly
- Cell membrane – encloses contents of the cell and maintains the cell’s shape; regulates passage of substances
State the structure and function of the following:
- Lysosome
- sER
- rER
- Lysosome – produces hydrolytic enzymes that aid in digestion and excretion of substances
- sER – network of tubes and flat curved sacs that helps to transport materials through the cell; main location of fat metabolism
- rER – folded membranes studded with ribosomes, helps transport of materials through the cell; site of protein manufacture
State the structure and function of the following:
- Golgi complex
- Mitochondrion
- Golgi complex – a structure that processes and repackages proteins produced in the rER for release at the cell membrane
- Mitochondrion – site of fat and sugar digestion in the cell (cellular respiration), produces energy
What are the two types of chromatin?
- Chromatin is found in two varieties: euchromatin and heterochromatin
- Heterochromatin stains more intensely, indicating tighter packing
What is limit of resolution?
Limit of resolution – the minimum distance at which two objects can be distinguished
Outline the general structure of prokaryotic cells
- Prokaryotic cells have an external membrane but no internal membranes
- All the biochemical processes of the cell occur in the same compartment
Identify 7 primary components of the prokaryotic cell
- Capsule
- Cell wall
- Plasma membrane
- Flagella
- 70s Ribosomes
- Nucleoid
- Pili
Outline the general structure of a eukaryotic cell
- Eukaryotic cells are compartmentalised by internal membranes
- Hence, eukaryotic cells have a true nucleus and true organelles
Identify 10 primary components of the eukaryotic cell
- Plasma membrane
- Vacuole
- Nuclear envelope
- Nucleolus
- Chromosomes
- Lysosome
- rER and sER
- Golgi Complex
- Free ribosomes
- Mitochondria
Describe the structure of plasma membranes
- Composed of a phospholipid bilayer
- Ampipathic
- Associated membrane proteins: Integral and peripheral proteins
Describe 5 functions of the plasma membrane
- Selective permeability
- Transport of materials along cell surface
- Endocytosis and exocytosis
- Intercellular recognition
- Barrier to water-soluble molecules
What is glycocalyx?
- The glycocalyx is the cell coat
- It is made up of oligosaccharide and polysaccharide side chains on the outside of the plasma membrane
Outline 4 features of the Fluid Mosaic Model
- Hydrophobic fatty acid tails in the middle
- Hydrophilic heads on the outside
- Membrane proteins: integral proteins, peripheral proteins
- Phospholipids form a bi-layer
Describe the structure of the endoplasmic reticulum
- ER membrane is continuous and encloses a single lumen
- sER does not have ribosomes attached
- rER has ribosomes attached
Distinguish between free and bound polyribosomes in terms of protein production
- Free polyribosomes synthesise proteins which remain in the cytoplasm
- Bound polyribosomes show protein synthesis and segregation into the rough ER
Describe the role of the Golgi apparatus in the cell
The Golgi apparatus functions to modify, sort, concentrate and package proteins synthesised on the rough endoplasmic reticulum
Outline the structure and function of lysosomes
- Structure: generated by the Golgi apparatus and contain many hydrolytic enzymes
- Function: fuse with material requiring digestion
Distinguish between primary and secondary lysosomes in terms of their formation and function
- Primary lysosome:
I. Formed from the Golgi apparatus
II. Does not release intracellular contents
- Secondary lysosome:
I. Formed by the fusion of the primary lysosome and an endocytotic/phagocytotic vesicle
II. Releases intracellular contents/waste products
Describe the structure and function of mitochondria
- Structure: double membrane, DNA, ribosomes and division similar to bacteria
- Function: ATP generation by oxidative phosphorylation
How are mitochondrias inherited?
Female lineage
Identify 4 functions of the cytoskeleton
- Determines the shape of animal cells
- Ensures movement of cells
- Structural support and movement of cell organelles
- Provides the framework for moving and separating cells during cell division
What are microtubules?
Microtubules are long hollow cylinders made of the protein tubulin
Where are microtubules found?
Sites where structures are moved (i.e. nerve fibres, the mitotic spindle, cilia and flagella)
