EUKARYOTIC CELL Flashcards
WHAT DOES THE NUCLEUS CONTAIN?
-chromatin (DNA and proteins which make up the chromosomes (nucleosomes))
-nuclear envelope (inner & outer membrane which bounds nucleus
against rest of the cell, nuclear pores)
-nuclear lamina (made of lamins)
-nucleolus (ribosome production site)
-nuclear pores (ensures communication with cytoplasm - strictly regulated passing of substances)
WHAT ARE INTERNAL MEMBRANES OF THE CELL?
- membrane-bounded organelles →
compartmentalization of cell inside
WHAT ARE THE ROLES OF THE PLASMA MEMBRANE?
(1) import and export of molecules,
(2) attachment of cells to other cell or to extracellular matrix
(3) receiving information from the environment and
(4) cell movement
WHAT IS THE FLUID-MOSAIC MODEL?
-describes how the membrane is fluid, flexible and made of many different components or macromolecules which allows the membrane to move with the cell and perform various functions, including maintaining homeostasis, facilitating cellular movement, communication and more.
(phospholipids, carbs, proteins, cholesterol)
WHAT ARE CHROMOSOMES?
-A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes. Each chromosome contains a single long double helix of DNA wrapped around a protein and each carries several genes
WHAT IS THE CELL WALL?
-only plants and fungi have this rigid wall made of cellulose, hemicellulose and pectin. It forms and external skeleton for protection and mediates cell - cell communication
WHAT ARE THE LOCOMOTARY PARTS OF THE EUKARYOTIC CELL?
-flagella = movement
-cilia = surface of epithelial cells, removes pathogens
WHAT OCCURS IN THE CYTOPLASM?
-mRNA translation
WHAT IS THE CYTOSOL?
-gel / liquid part of plasma membrane without the membrane bound organelles
-contains ribosomes, cytoskeleton and cell cortex (actin filaments below plasma membrane (forms contractile ring during mitosis) )
WHAT ARE THE 3 TYPES OF CYTOSKELETON FILAMENTS?
-microtubules (tubulin)
-intermediate filaments (keratins, vimentin, lamins)
-actin filaments
WHAT IS THE MITOCHONDRIA?
-powerhouse of the cell
-double membranous structure
-inner membrane folds to form a cisternae which increases surface area and ATP synthesis via oxidative phosphorylation - mitochondrial matrix
-have their on mtDNA (human has 13 proteins), circular double stranded DNA, 16,500bp, 37 genes, maternally inherited
-70S ribosomes
-cristae enable compartmentalisation = can be lamellae or tubular (which needs lipid droplets and smooth endoplasmic reticulum)
-many proteins imported from nucleus through the cytosol as outer membrane is a permeable protein channel
mtDNA disease = Kearns-Sayre syndrome (eye disorder)
HOMOPLASMY = presence of 1 genotype of mtdna
Leber optical neuropathy (ND4)
HETEROPLASMY = presence of 2 or more genotypes of mtdna
myoclonic epilepsy / ragged red fibre syndrom (MERRF), mitochondrial encephalomyopathy / lactic acidosis / stroke like episodes (MELAS), neurogenic muscle weakness / ataxia and retinitis pigmentosa (NARP)
NUMTOGENESIS = mtdna transfer from mitochondria to nuclear dna
WHAT IS THE GOLGI COMPLEX?
-involved in the packaging and exporting of proteins via vesicles
-flattened disc shaped cisternae
CIS = ENTER
TRANS = exit
WHAT IS THE ENDOPLASMIC RETICULUM?
-network of tubes that frow from the nuclear membrane, double membraned
-RER = ribosomes present, synthesis or membrane and organelle proteins + modification of proteins (glycosylation, formation of disulfide bonds, chaperones) (usually spread out)
-SER = ribosomes absent, synthesis of phospholipids and fatty acids, steroids, modification of proteins (glycosylation) (looks like a C shape)
-FREE RIBOSOMES = make proteins too
WHAT ARE PEROXISOMES?
-reactions where hydrogen peroxide is produced and degraded
WHAT ARE VACUOLES?
-large membrane-bounded vesicles, only in plants, containing water solutions of substances (ions, saccharides etc.)
WHAT ARE LYSOSOMES?
-single membranous structure filled with digestive enzymes which helps to digest worn-out cells and foreign bacteria and viruses
LYSOSOMAL DISEASE = Gaucher syndrome (accumulation of substrate)
