Module 2- Cell Structure Flashcards
what is a lysosome?
-specialised vesicle
-contains hydrolytic enzymes to break down waste material
why is the membrane around the lysosome important?
-compartmentalises enzymes away from cell structures that could damage them
what is the cytoplasm composed of?
cytosol- made up of water, salts and organic molecules
what is the function of the smooth endoplasmic reticulum?
-lipid synthesis
-carbohydrate synthesis
-storage
what are the similarities between prokaryotic cells and eukaryotic cells?
-ribosomes (different sizes)
-cell surface membranes
-cytoskeleton (different structure however)
what does a prokaryotic cell have that a eukaryotic cell doesn’t?
-smaller ribosomes
-cell walls of peptidoglycan
-unicellular cell type
-reproduced by binary fission
-circular DNA
-plasmid extra-cellular DNA
-flagella made of flagellin
what does a eukaryotic cell have that a prokaryotic cell doesn’t?
-membrane bound organelles
-cell walls of chitin/cellulose
-multicellular cell type
-linear DNA
-membrane bound DNA (nucleus)
-mitochondria
-flagella made from microtubules (9+2 formation)
what is the cell wall of a prokaryotic cell made of?
peptidoglycan
what is the function of the nucleolus?
produces ribosomes
where is the nucleolus found?
within the nucleus
what is the function of mitochondria?
site of aerobic respiration
what is the function of cytoskeleton
cell movement, organelles movement, holds organelles in place—- necessary for shape + stability of cell
what is the function of lysosomes?
-break down waste material in cells e.g. old organelles
-break down pathogens
what is the function of the centrioles?
-involved in formation of spindle fibers in cell division (centrosome)
-responsible for positioning of flagella/cilia
what are centrioles?
-component of cytoskeleton
-composed of microtubules
what is the function of rough endoplasmic reticulum?
-synthesis of proteins
-transport of proteins
what are the endoplasmic reticulums?
network of membranes enclosing flattened sacs called cisternae
what is the function of the chloroplast?
-responsible for photosynthesis in plant cells
what part of the plant are chloroplasts found?
leaves and stems (green parts)
what is the fluid in the chloroplast called and what does it contain?
stroma- contains chlorophyll for light dependent reactions during photosynthesis
what structure are in the chloroplast?
thylakoids: network of membranes which form flattened sacs
grana: several thylakoids stacked together joined by membranes called lamellae
starch grains: produced through photosynthesis
what is the function of the cellulose cell wall?
-gives a plant its shape
-acts as defence mechanism by protecting the cell contents from pathogens
-allows turgidity as it is permeable
what are fungi cell walls made of?
chitin
what are the three components of the cytoskeleton?
microfilaments, microtubules, intermediate fibres
what do the intermediate fibres of the cytoskeleton do?
give mechanical strength to cells and maintain their integrity
what do the microfilaments of the cytoskeleton do?
responsible for ENTIRE cell movement (not organelles) + cell contraction during cytokinesis
how does the cytoskeleton move organelles around the cell?
using microtubules
what do the microtubules of the cytoskeleton do?
determine shape of the cell + aid organelles in moving around the cell
-spindle fibres involved in segregating chromosomes are composed of microtubules
what is the function of the golgi apparatus?
modifies proteins and packages them into vesicles
-could be secretory vesicles if designed to leave cell
-or could be lysosomes if they stay in cell
what are the enclosing flattened sacs on endoplasmic reticulum and golgi apparatus called?
cisternae
what is the function of the ribosome?
site of protein synthesis
what organelles contain ribosomes?
chloroplast, mitochondria, (prokaryotic cells also)
where in the cell are ribosomes found and what structure do they have?
-found on RER or free floating in cytoplasm
-not membrane bound + made of RNA molecules
what is the structure of the mitochondria?
-double membrane
-inner membrane folds into cristae
-fluid inside called matrix- contains enzymes needed for aerobic respiration
-mitochondrial DNA (circular)
can mitochondria reproduce themselves?
yes, they also produce their own enzymes
what happens during aerobic respiration?
energy stored in bonds of complex organic molecules is made available to use by the production of the molecule ATP
what is the function of flagella?
enables cell mobility and in some cells detects chemical changes in a cells environment
what is the structure of flagella and cilia?
9+2 arrangement (two central microtubules surrounded by nine pairs of microtubules
what are the two cilia types?
mobile and stationary
what do mobile cilia do and where are the found?
beat in rhythmic pattern causing fluids/objects to move e.g. in trachea to move mucus away from lungs and in fallopian tubes to move egg cells from ovary to uterus
what do stationary cilia do?
present at surface of many cells + play sensory role in organs like nose
how do cilia move in beating motion?
parallel pairs of microtubules slide over each other
what is the function of the nuclear envelope?
to protect DNA from damage in the cytoplasm
what is the structure of the nuclear envelope?
-double membrane
-has nuclear pores
what are the nuclear pores function?
allows molecules (RNA) to leave and enter nucleus to the RER (for protein synthesis)
what is the function of the nucleus?
contains DNA
what are the organelles involved in protein production?
-proteins are synthesised on RIBOSOMES bound to RER
-proteins are passed into RER cisternae to be packaged into transport VESICLES
-VESICLES move to GOLGI APPARATUS via CYTOSKELETON
-VESICLE fuses to cis face of GOLGI APPARATUS and proteins enter
-proteins are structurally modified in golgi and pinch off as vesicles
-vesicle is transported to and fuses to CELL SURFACE MEMBRANE and contents are released via exocytosis// some vesicles become LYSOSOMES which remain in cell
