biology: prokaryotes + eukaryotes Flashcards
(36 cards)
1
Q
What does the modern theory of cellular organisation state?
A
- all living things are composed of cells and cell products.
- new cells are formed only be pre-existing cells
- the cell contains inhereted info (genes), which is used as instructions for growth and development.
- the cell is the the functioning of life; metabolic reactions of life take place within the cells
2
Q
What is a eukaryotic cell?
A
- they make up multi-cellular organisms such as plant and animals
- they are a complex cell WITH A NUCLEUS and membrane bound organelles
3
Q
What is a prokaryotic cell?
A
- single-celled organisms
- simple structures and have NO NUCLEUS or any membrane bound organelles
4
Q
What happened in 1665?
A
- Robert Hooke observed a cell for the first time using compound microscope
- He created the term ‘cell’
5
Q
What happened in 1838?
A
- Matthias Schleiden stated all plants are made from cells
6
Q
What happened in 1839?
A
- Theodor Schwann stated all animals are made from cells
- this was the starting base of cell theory
7
Q
What happened at 1858?
A
- Rudolf Virchow determined all new cells must come from pre-existing cells
8
Q
What is the structure and function of mitochondria?
A
- sites of aerobic respiration
- C6H12O6 + 6O2 6H2O + 6CO2 + energy
- responsible for production of energy carrier molecule, ATP, from carbohydrates
9
Q
What is the structure and function of centrioles?
A
- hollow fibres made of microtubes
- two centrioles at right angles to each other form a centrosome - which organises spindle fibres during cell division
- not found in fungi and flowering plants
10
Q
What is the structure and function of nucleus?
A
Nucleus - act as control centre of cell through production of mRNA, hense protein synthesis
- retain genetic material of cell in form of DNA or chromosomes
Nucleolus - manufacture ribosomal RNA and ribosomes
11
Q
What is the rough endoplasmic reticulum?
A
- has ribosomes present on the outer surfaces of the membranes
- provides a large surface area for synthesis of proteins and glycoproteins
- provides a pathway for transport of materials, especially proteins, throughout the cell
12
Q
What is the structure and function of cytoplasm?
A
- the fluid in which the other organelles are found
- also where metabolic reactions take place
13
Q
What is the smooth endoplasmic reticulum?
A
- lacks ribosomes on its surface
- often more tubular in appearance
- function to synthesise, stores and transports lipids and carbohydrates
14
Q
What are the lysosomes?
A
- specialist forms of vesicles which contain hydrolytic enzymes (enzymes that break biological molecules down)
- break down material ingested by phagocytic cells, such as white blood cells
- release enzymes to the outside of the cell in order to destroy material around cell
- digest worn out organelles so useful chemicals they’re made of can be re-used
- completely break down cells after they have died autolysis
15
Q
What are ribosomes?
A
- site of translation in protein synthesis
- found in eukaryotic cells, 80S type
- each ribosome has 2 subunits - one large one small - each contain ribosomal RNA and protein
16
Q
What are the vesicles?
A
- membrane-bound sac for transport and storage
17
Q
What is the Golgi body? (short description)
A
- membrane bound organelle
- made of stacks of flattened membrane sacs
- has many functions
- more prevalent in secretory cells e.g. gland cells
18
Q
What is the Golgi body? detailed
A
- processing and sorting proteins: Golgi apparatus receives proteins from endoplasmic reticulum, processes and sorts them for transport to their destination
- packaging proteins: Golgi apparatus packages proteins into membrane-bound vesicles for transport to their destinations
- modifying proteins: Golgi apparatus modifies proteins as they make through it, attaching sugar monomers to them, to form glycoproteins
- synthesizing glycolipids
- synthesizing cell wall polysaccharides: in plant cell, Golgi apparatus synthesizes polysaccharides of the cell wall
19
Q
What cells are in most animal cells?
A
- mitochondria
- centrioles
- nucleus
- nucleolus
- rough endoplasmic reticulum
- cytoplasm
- smooth endoplasmic reticulum
- lysosomes
- ribosomes
- vesicles
- Golgi body
- cell membrane
20
Q
What extra cells are in a plant cell?
A
- cellulose cell wall
- large permanent vacuole
- amyloplasts
- chloroplasts
- plasmodesmata
21
Q
What is the function of the cellulose cell wall?
A
- provides support and shape to the cell
- prevents cell from bursting under pressure from water moving in
22
Q
What is a large permanent vacuole and it’s function?
A
- contains a solution of mineral salts, sugars, amino acids, wastes and anthocyanins
- vacuole has a single membrane around it called the tonoplast
23
Q
What is the role of the amyloplasts?
A
- specialised for the accumulation of starch in storage cells
- consists of a double membrane (envelope)
- responsible for the synthesis and storage of starch within plant cells
24
Q
What is the role of chloroplasts?
A
- site of photosynthesis
- more concentrated in cells responsible for photosynthesising
- contains pigment chlorophyl
- chloroplasts contain 70S ribosomes (much smaller, similar to a prokaryotic cell)
25
What is the role of the plasmodesmata?
- microscopic channels which cross the cell walls of plant cells
- extensions of cytoplasm between cells
- enables transport and communication between individual plant cells
26
What do prokaryotic cells include?
- filled with cytoplasm
- contain very few internal structures
- genetic info is carried on circular pieces of DNA
- only organelles present is 70S ribosomes (makes proteins needed)
- include archaea, bacteria and cyanobacteria
27
Explain the prokaryotic structure - cell wall
- made of murein/peptidoglycan
- protects and supports cell
- physical barrier
- protects against mechanical damage (cell bursting if excess water diffuses into the cell)
28
Explain the prokaryotic structure - capsule
- bacteria protect themselves by secreting a capsule of slime around their cell wall
- made of hydrophilic polysaccharides
29
What is the function of a bacterial capsule?
- protecting from dehydration
- protecting from immune cells
- adhering to surfaces (helps stick)
- evading the immune system
- increasing pathogenicity
- trapping nutrients
30
Explain the structure of prokaryotes: cell membrane
- cell surface membrane is inside cell wall
- acts as differently permeable layer
- controls exit and entry of chemicals
31
Explain role of flagellum in prokaryotes:
- only some bacteria have it
- used to help a bacterium move
32
Explain structure of bacteria: cytoplasm
- fluid where other organelles are found
- where metabolic reactions occur
33
What is the function and role of DNA/nucleoid in bacteria?
- possesses genetic info for replication of bacterial cells
- DNA is found in nucleoid (region that holds nuclear material)
- no nuclear membrane
- DNA not associated with proteins and forms one circular chromosome
34
What is the role of plasmids in bacteria?
- circular pieces of DNA that reproduce themselves
- contain genes that aid the survival of bacteria
35
What is the role and structure of the pili in bacteria?
- hair like appendages that extend from surface of bacteria cell
- made from protein subunits called pilins which allows them to attach to other cells or surfaces
- aid in horizontal gene transfer
36
What are 70S ribosomes and their function?
- smaller than ribosomes of eukaryotic cells
- function is to synthesise proteins
