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
what is the Golgi apparatus?
- compact structure formed of cisternae
- modifies proteins, ‘packages’ them into vesicles
what is the cellulose cell wall?
- plant cell walls made of cellulose - a complex carbohydrate
- freely permeable, can move in and out of cell
- gives plant shape
- support individual cells and whole plant cell
- defence mechanism, protects cell contents
what are vacuoles?
- membrane lined sacs in cytoplasm containing cell sap
- many plant cells have large permanent vacuoles, very important for maintenance of turgor (rigid cell wall)
- vacuoles in animal cells are small and impermeable
what are chloroplasts?
- responsible for photosynthesis
- found in the green parts of plants (leave/ stems)
- double membrane structure
- an internal network of membranes, form flattened sacs called thylakoids
what is the fluid enclosed inside a chloroplast called?
stroma
what are the differences in DNA in prokaryotic cells and eukaryotic cells?
prokaryotic cells
- DNA is naked
- DNA is circular
- usually no introns
eukaryotic cells
- DNA is bound to protein
- DNA is linear
- usually has introns
what are the differences in organelles in prokaryotic cells and eukaryotic cells?
prokaryotic
- no nucleus
- not membrane bound
- 70S ribosomes
eukaryotic
- has nucleus
- membrane bound
- 80S ribosomes
what are the differences in reproduction in prokaryotic cells and eukaryotic cells?
prokaryotic
- binary fission
- single chromosome (haploid)
eukaryotic
- mitosis and meiosis
- paired chromosomes (diploid)
what are the differences in average size of prokaryotic cells and eukaryotic cells?
prokaryotic
- smaller (1-5μm)
eukaryotic
- larger (10-100μm)
