2.1.1 cell structure Flashcards
name functions of the cytoskeleton. (6)
- provides mechanical support for the cell
- holds organelles in place
- enable cell to cell signalling
- forms mitotic and meiotic spindle fibres so chromosomes can move
- forms tracks for motor proteins
- allows changing of cell shape eg cytokinesis
how does the cytoskeleton move organelles around the cell?
- using microtubules or motor proteins
what’s the function of the nucleus?
- stores the cells DNA
- controls cells activities
what’s the role of the rough endoplasmic reticulum? (2)
- folds and processes proteins made at the ribosome
- transports substances through the cisternae
function of smooth endoplasmic reticulum ?
- process and synthesise lipids
function of lysosome ?
- has hydrolitic enzymes to digest dead cells, pathogens and foreign objects
how is a protein prepared and secreted after translation? (7)
- transport vesicle from RER
- to the Golgi body
- for modification
- then packaged into a secretory vesicle
- secretory vesicle moves along the cytoskeleton
- it fuses with the cell surface membrane
- then secreted by exocytosis
what is the role of ribosomes
- site of protein synthesis
what is the role of the cellulose cell wall? (2)
- supports plant cells and prevents it from bursting when they are turgid
- allow solutions to pass through since they are permeable
what is the role of the flagella?
- tail-like structure that help cells move
what’s the role of the nucleolus?
- where ribosomes are made
what is the role of the centrioles?
- separate chromosomes during cell division
- form the cilia and undulipodia
what is the role of the nuclear envelope?
- separates contents of the nucleus from the rest of the cell
what is the role of the golgi body? (2)
- makes lysosomes
- modifies and packages proteins and lipids into vesicles
what is the role of the mitochondria ?
- site of aerobic respiration, producing ATP
what is the role of chloroplasts?
- site of photosynthesis
what’s the role of the plasma membrane? (6)
- regulates the movement of substances into or out of a cell
- enables cell to cell signalling
- creates concentration gradients
- enables cell to cell recognition
- compartmentalisation: a barrier between the cell contents and the external environment
- site of chemical reactions
what is the role of the vacuole?
- maintains cell stability, by keeping the cell turgid, thus supporting the whole cell
how do eukaryotic cells divide?
what type of reproduction is this
- by mitosis or meiosis
-mitosis is asexual , and meiosis is sexual reproduction
how do prokaryotic cells divide?
what type of reproduction is this?
- by binary fission
- asexual reproduction
do eukaryotic cells have membrane bound organelles?
yes
do prokaryotic cells have membrane bound organelles?
no
describe the cells genetic material in eukaryotic cells? (3)
- in the nucleus
- linear DNA
- associated with proteins
describe the cells genetic material in prokaryotic cells (2)
- in chromosomal DNA or plasmids
- no protein association
what is a prokaryotic cell wall made of?
- peptidoglycan
what is a eukaryotic cell wall made of if it’s present?
- cellulose (plants)
- chitin (fungi)
do eukaryotic cells have a cytoskeleton?
yes
do prokaryotic cells have a cytoskeleton?
- no.
- if they do, it’s very simple
are eukaryotic cells multicellular or unicellular?
- often multicellular
are prokaryotic cells multicellular or unicellular?
- always unicellular
do prokaryotic cells have a true nucleus?
- no, DNA kept in plasmids
do eukaryotic cells have a nucleus?
- yes, encased with a nuclear envelope
similarities between eukaryotes and prokaryotes (3)
- both have ribosomes
- both have some form of DNA
- both have cytoplasm and a plasma membrane
what is the role of the nuclear pores? (1)
- allows movement of molecules in and out of the cell
role of the cilia / undulipodia ? (3)
- has receptors to allow the cell to detect signals about its environment
- sperm has undulipodia to move
- moves substances along the cell surface eg mucus
what is differential staining?
- when different dyes are used to differentiate between different cells or orangelles.
why do we stain in light microscopy?
- so internal structures are more visible
- to increase contrast
- to distinguish between cell types
