Chapter 2.3 - Eukaryotic cell structure Flashcards
What are eukaryotes?
Multicellular eukaryotic(cells with a nucleus and other membrane-bound organelles) organisms
What is the ultrastructure of a cell?
The components of a cell that can be seen using an electron microscope
What is an organelle?
Membrane-bound compartments with varying functions inside eukaryotic cells
What are the main organelles of a eukaryotic cell?
- Cytoplasm
- Centrioles
- Cilia
- Endoplasmic reticulum : smooth and rough
- Golgi apparatus
- Lysosomes
- Mitochondria
- Nucleus
- Nucleolus
- Plasma membrane
- Ribosomes
- Vesicles
What is the structure and function of the nucleus?
- Contains chromosomes(linear DNA strands and associated to histone proteins) and one or more nucleoli(skeletal muscles)
- Surrounded by a double membrane structure, nuclear envelope, with a number of pores to control exchange between the nucleus and cytoplasm
- It stores DNA and coordinates the cell’s activities, which include growth, intermediary metabolism(synthesises various enzymes), protein synthesis and reproduction
What is the structure and function of the nucleolus?
- It is composed of proteins and RNA
- It is an area within the nucleus and is responsible for the synthesis of ribosomes
What is the structure and function of mitochondria?
- 1 to 10 μm long rod-shaped organelle
- Has a smooth outer membrane and inner membrane highly folded into cristae
- The matrix(fluid region inside inner membrane) contains enzymes for respiration and has their own DNA - mtDNA
- Carries out aerobic respiration in the matrix and on the cristae, producing ATP
What is the structure and function of vesicles?
- Membranous fluid-filled sacs that transport molecules to other parts of the cell or are secreted out of the cell
What is the structure and function of lysosomes?
- They are forms of vesicles that contain hydrolytic enzymes which are used for the intracellular digestion of macromolecules
- They also break down pathogens ingested by phagocytosis(lysozyme) and play a role in programmed cell death, apoptosis(if the cell gets damaged, then one of the lysosomes bursts and releases its hydrolytic enzymes which digests the cell)
What is the function of cytoplasm?
- Suspends the internal components of cells in place and protects them from damage by cushioning and guarding genetic material and organelles against harm caused by movement and collision with other cells
What is the cytoskeleton?
It is a network of fibres necessary for the shape and stability of a cell
What are the three main functions of the cytoskeleton?
- To provide mechanical strength to the cell, reducing squashing
- Aiding transport within cells including whole organisms by forming tracks along which organelles can move
- Enabling cell movement
What are the three main components of the cytoskeleton?
- Microfilaments
- Microtubules
- Intermediate fibres
What is the structure and function of microfilaments?
- Contractile fibres formed from the protein actin, 7nm in diameter
- Responsible for: whole cell movement(phagocytosis) and cell contraction during cytokinesis
What is the structure and function of microtubules?
- 18-30nm in diameter
- Made of globular tubulin proteins which polymerise to form tubes which form a scaffold-like structure, determining the shape of a cell
- Acts as tracks for organelles to move along(e.g. vesicles)
- Form spindle fibres which separate chromosomes during cell division