2.4 - Eukaryotic Cell Structure Flashcards
What are the functions and features of the nucleus?
- Contains DNA which directs protein synthesis
- Controls cell activites such as metabolism
- Largest organelle
What are the features & functions of the nuclear envelope?
- Separates genetic material from cytoplasm - protecting from damage
- Has nuclear pores allowing mRNA from nucleus to ribosomes
What are the features and functions of the nucleolus?
- Situated inside the nucleus
- Produces ribosomes
- Has proteins and RNA
Give the structure & function of mitochondria
- Outer mitochondrial space: separates mitochondria contents from rest of cell, compartmentalising for aerobic respiration
- Matrix: Contains enzymes for Krebs cycle and link reaction – also has mtDNA
- Intermembrane space: Proteins pumped into this space by ETC. Conc. of the proteins builds up quickly due to its size
- Inner mitochondrial membrane: Has ETC and ATP synthase
- Cristae: Projections of inner membrane – increase the SA for oxidative phosphorylation
What are vesicles?
What are lysosomes?
Vesicles:
Membranous sacs that store and transport substances inside a cell
Lysosomes:
Specialised vesicles with hydrolytic enzymes to break down pathogens and dead cell contents (old organelles)
What are the components of the cytoskeleton and what is the role of the cytoskeleton?
- Role in giving mechanical/structural support, enables organelle and whole cell movement
- Comprised of microfilaments, microtubules & intermediate fibres
Describe the role and structure of microfilaments, microtubules & intermediate fibres
Micorfilaments: Has actin (contracticle protein) which is responsible for cell movement and cell contraction in cytokinesis (making 2 daughter cells)
Microtubules:Globulartubuiln polymerises to give a scaffold-like structure to create cell shape
- Have role in moving organelles, vesicles and spindle fibres
Intermediate Fibres: Give mechanical strength
What is the role and structure of centrioles?
- Composed of microtubules
-
2 centromeres is a centrosome
- Involved in spindle fibre organisation
- Have role in positioning cilia & flagella
What is the role of flagella?
- Whip-like extension from cells
- Longer than cilia but flagella are fewer in number
- Enables cells motility (ability for a cell to independantly move)
- Sensory organ - detecs chemical changes in cell
Give the structure and function of cilia.
- Stationary cilia act as sensory organelles in sensory organs (e.g. nose)
-
Mobile cilia beat to cause fluids or objects adjacent to the cell to move
- E.g. mucus in trachea
- E.g. egg cell in falopian tube, from ovary to uterus
Describe the structure of cilia.
- Has 2 central microtubules
- 9 pairs of surrounding microtubules arranged in a wheel
- Known as 9+2 arrangement
- Pairs of microtubules slide over one another to cause cilia movement
- Known as 9+2 arrangement
What are the protein synthesis organelles?
ER (rough and smooth)
Ribosomes
Golgi apparatus
What are the 2 types of ER and their functions?
What is the structure of endoplasmic reticulum?
Smooth ER: Lipid and CHO synthesis and storage
Rough ER: Ribosomes bound to surface for synthesis and transport of proteins
- Network of flattened sacs called cisternae - connected to outer surface of nucleus
What are the features of ribosomes?
- Site of protein synthesis
- Can be free-floating or attached to ER (making it rough ER)
- Made of RNA from the nucleolus
What are the features of the Golgi Apparatus?
- Formed of cisternae
- Role in modifying proteins made in ribosomes - often adds CHO group
- Repackages proteins into vesicles to leave or stay in cell
