1.2 Cell Structure Flashcards
Nucleus
contains DNA coding for protein synthesis in cytoplasm and controls cell activity
Nucleus Features
Nuclear envelope, Nuclear Pores, Nucleolus
Nucleus Size
5µm to 10µm
Chloroplasts
(ONLY IN PLANT CELLS) contains chlorophyll - site of photosynthesis
Chloroplast Features
Stroma, Grana, Thylakoids, Starch Grains, 70S Ribosomes, Circular DNA
Chloroplasts Size
0.5 - 2 µm wide and 10 µm in length
Mitochondria
Produces ATP by aerobic respiration
Mitochondria Features
Cristae, Matrix, 70S Ribosomes, Circular DNA
Mitochondria Size
1 µm in length
Protein Transport within the cell
1) Proteins are made by ribosomes on rough endoplasmic reticulum and are pinched off into vesicles
2) Vesicles containing the proteins fuse to the Golgi Body, where they are modified
3) Vesicles containing modified proteins break away from the Golgi Body
4) Vesicles fuse with the cell surface membrane by exocytosis, releasing protein outside the cell
Rough Endoplasmic Reticulum Function
ribosome and protein synthesis
Smooth Endoplasmic Reticulum Function
lacks ribosomes which synthesises lipids and steroids ie. cholesterol
Golgi Body Function
glycoprotein synthesis, protein modification / packaging in vesicles for export from cell
Lysosomes
Contains Hydrolytic Enzymes that digests unwanted materials and worn-out organelles
Lysosomes Size
0.1-0.5 µm
Cell Surface Membrane Function
controls movement of substances in and out of cell - partially permeable
Cell Surface Membrane Thickness
7 nm thick
Cell Wall Function
(ONLY IN PLANT CELLS) made of cellulose which supports the cell by maintaining its shape
- Keeps cell firm / prevents turgidity
- Provides mechanical strength
Plasmosdesmata
(ONLY IN PLANT CELLS) microscopic channels which traverse the cell walls of plant cells and some algal cells, enabling transport and communication between them
Large Permanent Vacuole
(ONLY IN PLANT CELLS) might store food or any variety of nutrients a cell might need to survive
Tonoplast
The membrane surrounding the large permanent vacuole
Centrioles
(ONLY IN ANIMAL CELLS) a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
Centrioles Size
0.5 µm
Microtubules Function
- Forms cytoskeleton along with thinner protein filaments
- Involved with movement of organelles via special attachment proteins
ATP stands for
Adenosine triphosphate
ATP function
- It is the universal energy currency of the cell
- “immediate source of energy for the cell. When ATP is broken, a small packet of energy is released
ATP hydrolysis reaction
ATP + water → ADP + phosphate + energy
Features of Prokaryotes: organelles, DNA, ribosome type, flagella, cell wall material
- No nucleus and double membrane-bounded organelles; mitochondria & chloroplasts
- Naked / circular DNA - contains plasmids
- 70S ribosomes
- Flagella lacks 9+2 microtubule arrangement [single]
- No ER, Golgi body and lysosomes
- Cell wall made of peptidoglycan (murein)
Features of Eukaryotes: organelles, DNA, ribosome type, flagella, cell wall material
- Nucleus and double membrane-bounded organelles present
- Linear DNA
- No plasmids
- DNA associated with histone proteins
- Contains ER along with Golgi body and lysosomes
- 70S & 80S ribosomes
- Flagella contains 9+2 microtubule arrangement
- Cell wall made mostly of cellulose / chitin (fungi)
Virus
an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host - DNA or RNA of Virus takes over the protein synthesising machinery of host cell and helps to make new virus particles
Virus Features
- No nucleus and cytoplasm
- Consists of genetic material contained within a protein coat (capsid) - made up of many individual protein molecules called ‘capsomeres’
- Symmetrical shape
Virus Size
Ranges in size (20–300 nm)
Nucleolus
Nucleus - Synthesises rRNA and ribosomes (1-2 µm)
Nuclear envelope
Nucleus - Double membrane surrounding the nucleus
Nuclear Pores
Nucleus - Allows passage of large molecules ie. mRNA and ribosomal proteins to be transmitted out of the nucleus
Stroma
Chloroplast - Colorless fluid surrounding the grana within the chloroplast. enzymes necessary for light independent stage
Grana
Chloroplast - made up of flattened sacs; thylakoids
Thylakoids
Chloroplast - An internal system of interconnected membranes, that carry out the light reactions of photosynthesis
Starch Grains
Chloroplast - Acts as temporary stores of carbohydrates produced
Cristae
Mitochondria - inner membrane folded
Matrix
Mitochondria - Krebs cycle & oxidative phosphorylation takes place here
Cisternae
Endoplasmic Reticulum - Membranes enclose a network of tubules and flattened sacs; cisternae
