Prokaryotic And Eukaryotic Cells Flashcards
How does the size differ between prokaryotic cells and eukaryotic cells?
Prokaryotic cells are small, about 0.1 - 10 micrometers
Eukaryotic cells are larger, about 10 - 100 micrometer
What is the complexity like of a prokaryotic cell?
They are simple and make up unicellular organisms like bacteria.
What is the complexity like of a eukarytoic cell?
They are larger more complex cells which make up multicellular organisms like animals and plants
Where is DNA found in prokaryotic cells?
It is fee floating in the cytoplasm in an area called the nucleoid.
What is the structure of the genetic material in prokaryotic cells?
DNA is a double helix
DNA has a circular structure
DNA is not associated with proteins
What is the extra DNA in prokaryotic cells called?
Plasmids.
What don’t prokaryotic cells have any of?
Membrane bound organelles
What size are the ribosomes like in prokaryotic cells?
70s
What is the cell wall made up of in prokaryotic cells?
Murein (glycoprotein - protein attached to a carbohydrate)
What is found on the outer layer of some prokaryotic cells?
A slime capsule (protects against attack of cells in immune system)
Do prokaryotic cells have a cytoplasm?
Yes
Do prokaryotic cells have a cell membrane?
Yes
What do some prokaryotic cells have to move?
Flagella
Where is DNA found in eukaryotic cells?
In the nucleus (membrane bound)
What is the structure of DNA in eukaryotic cells?
DNA is a double helix
DNA is associated with his tone proteins
DNA is linear
No plasmids
What are most organelles surrounded by in eukaryotic cells?
Phospholipid bilayer (membrane bound organelles)
What is the size of ribosomes in eukaryotic cells?
80s
What is the only organelle which isn’t membrane bound?
Ribosomes
What is the cell made out of in eukaryotic cells (plants/fungi)?
Plants = cellulose
Fungi = chitin
What type of channels do cellulose cell walls sometimes have?
Plasmodesmata (channels for exchanging substances)
Do eukaryotic cells have a protective outer layer
No slime capsule but do have a vacuole to aid rigidity
Do eukaryotic cells have a cytoplasm?
Yes
Do eukaryotic cells have a cell membrane?
Yes
Can eukaryotic cells have a flagellum?
Yes (only sperm cells)
How do prokaryotic cells divide?
Binary fission
What is the function of the nucleus?
- controls the cells activities (by controlling transcription of DNA and protein synthesis)
- contains the organism’s genetic material
Describe the structure of the nucleus
The nucleus is contained within a nuclear envelope which contains nuclear pores
Inside the nucleus there is a nucleolus and chromatin
What is the purpose of the nuclear envelope?
The double membrane around the nucleus and connects to the endoplasmic reticulum whilst controlling the entry and exit of materials
What is the purpose of nuclear pores?
Allows the movement of large molecules (mRNA) out of the nucleus
What is the function of the nucleolus?
Manufactures and resembles ribosomes from rRNA
What is the purpose is chromatin?
DNA exists as this is in the nucleus and condenses into chromosomes during cell division
What is the function of rough endoplasmic reticulum (RER)
Folds and processes proteins made at ribosomes before budding off into vesicles for transpiration
Why is the endoplasmic reticulum rough?
It has ribosomes on it
What is the function of smooth endoplasmic reticulum (SER)
Synthesise and transport lipids and carbohydrates
What is cisternae?
The membranes form a network of tubules and flattened air sacks ( endoplasmic reticulum and Golgi apparatus)
What is the function of chloroplast?
Contain chlorophyll for absorption of light for photosynthesis (converts light to chemical energy by phosphorylation to produce ATP)
What is the stroma in chloroplast?
Stroma is a fluid filled space filling the rest of the chloroplast and it’s where the second stage of photosynthesis occurs (synthesis of sugars)
What is the grana in a chloroplast?
They are stacks of disc like structures called thylakoids
What is the thylakoid?
Contains photosynthetic pigment (chlorophyll) so absorbs sunlight for photosynthesis (provides a large surface area).
What is lamellea?
Connective tissue joining adjacent grana
Where are the energy stores in chloroplasts?
Starch grains in the stroma store glucose made form photosynthesis
What are the internal structures of a chloroplast?
- have a double helix membrane, grana, thylakoids, lamellae and stroma
What are the structures of a mitochondria?
Outer membrane, inter-membrane space, inner membrane, Cristae, matrix, 70s ribosomes and circular DNA
What type of ribosomes do mitochondria have?
70s
What is the function of mitochondria?
Site of aerobic respiration which produces ATP (immediate energy source)
What is the purpose of cristae?
The inner membrane is folded to form this and aerobic respiration occurs here.
What is the purpose of the matrix?
Contain ribosomes, circular DNA and all enzymes required for respiration
What is the function of the Golgi apparatus?
It processes, modifies and packages new lipids and proteins for transportation
What does the Golgi apparatus do?
Modifies and packages proteins before budding off into Golgi vesicles and travelling to their destination.
What makes lysosomes?
The Golgi apparatus
How are lysosomes formed?
Form when vesicles that bud off Golgi apparatus contain hydroelectric enzymes.
What is the function of lysosomes?
-hydrolyse material taken up by phagocytise cells
- digest old organelles
- breaks down dead cells
What is the function of ribosomes?
Site of protein synt
Where are the ribosomes found?
Cytoplasm or rough endoplasmic
What are proteins made from?
rRNA and protein
Small sub-unit and large sub-unit
What are the two sizes of ribosomes?
70s and 80s
What is the function of a vacuole?
- helps maintain pressure in the cell and support plant by making cells turgid/rigid
- store useful ,substances (water,sugar and amino acids)
- isolate unwanted / harmful products in the cell
What is a vacuole?
A tonoplast membrane filled with fluid
What is the function of a cell membrane?
Regulates the movement of substances into and out of the cell
What is the function of the cell wall?
Provides the cell with strength to prevent it bursting due to osmotic gain/loss of water
What is the function of centrioles?
- support the cells shape
- form spindles during cell division.
How do organelles in a cell work together to produce and transport a protein?
- mRNA copies gene sequence
- mRNA leaves the nucleus via nuclear pores and attaches to the rough endoplasmic reticulum
- mRNA attaches to the ribosome which makes new proteins using the code from the RNA, the proteins are then packaged and transported in vesicles.
- Vesicles bid off the endoplasmic reticulum and travel towards the Golgi apparatus
- Vesicles fuse the the Golgi apparatus
- Golgi apparatus packages and modifies the proteins ready for release
- Golgi vesicles bud off Golgi apparatus and are labelled and transported to their destination
- Golgi vesicles fuse to plasma cell membrane.
- Exocytosis as protein is released outside the cell
What theory suggests eukaryotic cells enveloped from prokaryotic cells?
Endosymbiotic theory
How does the endosymbiotic theory suggest how mitochondrion and chloroplasts evolve?
Evolved from engulfed prokaryotes (an aerobic prokaryote and a photosynthetic prokaryote) that once lived as independent organisms but evolved inside prokaryotic cells become chloroplasts and mitochondria.
Why did mitochondria evelove?
They provided the prokaryotic cells with a survival advantage - by providing ATP
Why did chloroplast evolve?
Provided a competitive advantage for the cell - provided an alternative energy source
What is the evidence to prove the endosymbiotic theory?
- circular DNA found in both mitochondria and chloroplasts
- 70s ribosomes found in both
- Both surrounded by a double plasma membrane
- Both divide by binary fission
What is a tissue
A group of similar cells organised in a structural unit working together to perform a specific function
What is an organ
More than one tissue working together to perform a specific function
What is an organ system?
Multiple different organs working together to perform a pacific function
What is an example of an organ?
Arterioles.
What does Acellular mean
The cell is not a cell (non-living)
Why are viruses Acellular
They don’t satisfy the living criteria (Mrs Gren)
What does MRS GREN stand for
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
What type of genetic material do viruses contain?
DNA or RNA
Where is the genetic material stored in a virus?
Inside a capsid
What do viruses have on their cell surface membrane?
Attachment proteins, which provide the ability to attach to a host cell
What are 2 features of viruses which are sometimes present (not always)
Lipid envelope
Reverse transcriptase (enzyme)
Describe viral replication
- virus attaches to host cell with its attachment protein which bind to the protein receptors on the host cell surface membrane
- the virus injects it’s genetic material into the host cell and this used to synthesise viral proteins
- new viral particles are assembled
- new viruses burst out of and damage/destroy the host cell