module 2 - 2.4 eukaryotic cell structure & 2.5 the ultrastructure of plants Flashcards
what is the nucleus?
- contains genetic information in the form of DNA molecules
- DNA directs the synthesis of all proteins required by the cell
- nuclear envelope contains nuclear pores
what does DNA stand for?
deoxyribonucleic acid
what is the nucleolus?
- area in nucleus that produces ribosomes
- made of proteins and RNA
what are mitochondrion?
- site of final stages of cellular respiration
- stores energy in bonds of complex, organic molecules
- has double membrane
- produce their own enzymes so can reproduce themselves
what is a vesicle?
- membranous sacs that have storage and transport materials in cells
- made of a single membrane with fluid inside
what is a lysosome?
- specialised form of vesicle that combine enzymes
- breaks down waste materials in cells and pathogens in immune system
what is the flagella?
- whip/hair-like extensions
- longer than cilia
- used as a sensory organelle - detect changes in cells environment
what is stationary cilia?
present on surface of many cells, have important functions in sense organs
what is mobile cilia?
- mobile cilia beat in a rhythmic manner, creating current
- pairs of parallel microtubules slide over each other
what is the structure of cilia?
- contains 2 central microtubules, surrounded by 9 pairs of microtubules
(wheel structure/ 9+2 structure)
what are the 2 types of endoplasmic reticulum?
rough endoplasmic reticulum
smooth endoplasmic reticulum
what is the endoplasmic reticulum?
- network of membranes inside a cell where proteins and other molecules move
- connected to outer membrane of the nucleus
what is the rough endoplasmic reticulum?
ribosomes bound to the surface, responsible for the transport and synthesis of proteins
what is the smooth endoplasmic reticulum responsible for?
lipid and carbohydrate synthesis
what are ribosomes?
- site of proteins synthesis
- constructed of RNA molecules
- not surrounded by a membrane