Cell organelles, structure and function Flashcards
Describe the structure and function of the nucleus/ organelles found inside:
Structure= Nuclear envelope, Nuclear pores, Nucleoplasm, Chromosomes, Nucleolus (smaller sphere inside which is site of rRNA and makes ribosomes)
Function= Site of DNA replication and transcription, contains genetic code
Describe structure and function of the Endoplasmic reticulum:
Structure= folded membranes called cisternae, rough have ribosomes on cisternae
Function= RER- protein synthesis, SER- Synthesis and store of lipids and carbohydrates
Golgi apparatus and vesicles structure and function:
Structure= cisternae, secretary vesicles pinch off from cisternae
function= add carbohydrates to proteins to form glycoproteins,
produce secretory enzymes,
secrete carbohydrates,
transport modify and store lipids, form lysosomes,
products are transported to cell surface in golgi vesicles where they fuse with the membrane and the contents is released.
Describe the function and structure of Lysosomes:
Structure= bags of digestive enzymes
Function= Hydrolyse cells,
completely break down dead cells (autolysis),
Exocytosis- release enzymes to outside of cell to destroy material,
Digest worn out organelles for reuse of materials
Describe the structure and function of mitochondria:
Structure= Double membrane, inner membrane called cristae, fluid within the centre called mitochondrial matrix, loop of mitochondria DNA
Function= Aerobic respiration,
Site of ATP production,
DNA to code for enzymes needed in respiration. Cisternae to provide a large surface area for the attachment of enzymes involved in respiration.
Describe the structure and function of Ribosomes:
Structure= 80s- eukaryotic cells, 70s- prokaryotic cells
function= protein synthesis
Structure and function of the Vacuole:
Structure= Filled with fluid surrounded by a single membrane called a tonoplast
Function= Make cells turgid and provides support,
temporary store of sugars and amino acids,
The pigments may colour petals to attract pollinators.
Describe the structure and function of a chloroplast:
Structure= surrounded by a double membrane, contains thylakoids, fluid filled stroma contains enzymes for photosynthesis.
Function= Site of photosynthesis
Describe the structure and function of the Cell wall:
Structure= Plants- made of microfibrils of the cellulose polymer, Fungi- made of chitin
Function= provides structural strength to the cell
Describe the structure and function of the cell membrane:
Structure= Phospholipid bilayer- molecules embed within and attached on the outside (proteins, carbohydrates, cholesterol)
Function= Controls the entrance and exit of molecules
Differences in prokaryotic and eukaryotic cells:
Prokaryotic-
cells are much smaller
no membrane bound organelles
smaller ribosomes
no nucleus
may contain (plasmids, a capsule around the cell, flagella)
What are plasmids?
Small loops of DNA which only carry a few genes, e.g antibiotic resistants genes (prokaryotic)
What is the function of the capsule?
Slimy layer made of protein,
Prevents the bacteria from desiccating and protects the bacteria against the hosts immune system
Name and describe 3 types of epithelial cells:
Cuboidal epithelium= cube shaped, one cell thick. found in kidney nephron and ducts of silvery glands
Columnar epithelium= elongated cells, found in oviduct and trachea, have cilia
Squamous epithelium= Flattened cells, form the walls of alveoli, and line the renal capsule of nephron
Describe skeletal muscles:
- attached to bones.
- bands of long cells or fibres
- chose whether or not to contract these muscles (voluntary muscles)
- Striped
Describe Smooth muscles:
- individual spindle shapes
-contract rhythmically - cannot control these muscles (involuntary muscles)
- found in the walls of blood vessels
- Unstriped
Describe Cardiac muscles:
- Only in heart
- contract rhythmically
- do not tire
- have stripes but lack long fibres
