Eukaryotic Cell Structure Flashcards
Nucleus Organelles
Nuclear envelope –double membrane controls the entry and exit to the nucleus
Nucleoplasm – granular jelly like substance
Nucleolus – manufacturers the ribosomal RNA and assembles the ribosomes
Nuclear pores – allow large molecules such as messenger RNA leave the nucleus
Chromatin – the DNA found in the nucleoplasm, diffused chromosomes when not dividing
Nucleus Function
The functions of the nucleus are:
Control centre of the cell through the production of mRNA and hence protein synthesis
Hold the DNA of the cell
Manufacture ribosomal RNA and ribosomes
Mitochondria Organelles
Inner membrane – Folded to form extensions called cristae which provide a large surface for enzymes involved in respiration
Matrix – semi-rigid material, containing proteins, lipids & DNA traces for it to make its own proteins
Mitochondria Function
Site of respiration
They produce ATP molecules which are the bodies energy carrier molecules.
Rough Endoplasmic Reticulum
RER has ribosomes on its outer surface:
Provides a large surface area for protein and glycoprotein synthesis
Pathway for transport inside the cell
Smooth Endoplasmic Reticulum
SER no ribosomes on its outer surface:
Synthesis, store and transport lipids and carbohydrates
Golgi Apparatus Organelle
tbc
Golgi Apparatus Function
Functions:
Add carbohydrates to proteins to form glycoproteins
Produce secretory enzymes
Secrete carbohydrates
Transport, modify and store lipids
Form lysosomes
Lysosomes
Functions:
Break down material ingested by phagocytic cells
Release enzymes to the outside of cells
Digest worn out organelles
Autolysis – break down a whole cell once it has died
Ribosomes
Ribosomes are granules (they have no membranes) and are found in all cells, sometimes in the cytoplasm as well as on the RER.
2 types:
80S type – in eukaryotic cells
70S type – in prokaryotic cells (slightly smaller)
Important for protein synthesis each contains 2 parts a small and large subunit which both contain protein and ribosomal RNA.
Chloroplasts Organelles
Stroma - Fluid filled matrix where the second stage of photosynthesis takes place. Contains starch grains.
Envelope (double plasma membrane)- that surrounds the chloroplast. It is highly selective.
Thylakoid - disc like structures containing chlorophyll (the first stage of photosynthesis takes place here).
Grana - stacks of up to 100 thykaloids.
Chloroplast Adaptations to their function include:
Granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes for the first stage of photosynthesis
The stroma fluid has all the enzymes for the second stage of photosynthesis
They contain the DNA and ribosomes to make the proteins for photosynthesis
Vacuoles
Fluid filled sac bound by a single membrane (tonoplast).
A plant vacuole contains a solution of mineral salts, sugars, amino acids, wastes and pigments known as anthocyanins.
Vacuoles Function
They support plants by making cells turgid
The sugars and amino acids can act as a temporary food store
The pigments may colour petals to make them attractive to insects
