Theme B: B2 Cells - B2.2 Organelles and Compartmentalization

Question 1

Cell compartmentalisation

Answer 1

Cell compartmentalization refers to the organization of cellular components into membrane-bound organelles in eukaryotic cells. This separation allows specific biochemical processes to occur in distinct areas, enhancing efficiency and preventing interference between incompatible reactions.

Question 2

reductionism

Answer 2

studying cells and how they work by reducing it to its component parts and studying each part individually.

Question 3

biochemical fractionation

Answer 3

fractionation refers to the seperation and isolation of specific chemical and/or structures so that detailed research can be carried out.

chatgpt: A laboratory technique used to separate and isolate different components of a cell (such as organelles, proteins, or nucleic acids) based on their physical and chemical properties, like size, density, or solubility. It often involves methods like centrifugation or chromatography to study the function and structure of specific cellular components.

Question 4

catabolic process

Answer 4

breaks a large molecule into smaller sub-parts (e.g. respiration)

Question 5

anabolic process

Answer 5

the reverse reaction of a canabolic process, here sub-parts are mbined to form larger moleucles (e.g. photosynthesis)

Question 6

cell fractionation (centrifugation)

Answer 6

Fractionation refers to the seperation and isolation of specific chemicals and/or structures to carry out detailed research. Cell fractionation allows the extraction of organelles from cells. Centrifuges are used to sepearte components of a cell by spinning it high speeds. separation occurs because of the different densities of the component parts.

process:
1) cells are first mized in a tube with the substances that break down the cell membrane
2) sakple is then spun at high speeds to isolate the different components by size and shape.
3) once separated, larer and heavier organelles are found at the bottom of the tube

Question 7

chromotography

Answer 7

very effective at isolatin pure subtances like amino acids, proteins, carbohyrdates, and plant pigments. a mixture of molecules is placed into a separating medium. the molecules seaprate out depending on their size and the speed with which they travel through the medium. there are several types including:
1) gel and ion exchange chromotography

Question 8

gel electrophoresis

Answer 8

separates different types of molecules by passing them through a gel using an electrical charge. the molecules are separated based on properties such as size and charge. commonly use din nucleic acid studies.

Question 9

which cell components are not organelles?

Answer 9

1) cell wall
2) cytoskeleton
3) cytoplasm

Question 10

examples of cell organelles

Answer 10

1) nucleus
2) vesicles
3) ribosomes
4) plasma membrane
5) cilia/flagella
6) mitochondria
7) Golgi apparatus
8) lysosomes
9) chloroplast

Question 11

what cell processes are responsible for the production of proteins?

Answer 11

1) transcription
2) translation

Question 12

transcription

Answer 12

DNA strand serves as a template or copy strond for the fomration of messenger RNA (mRNA) (happens in NUCLEUS)

Question 13

translation

Answer 13

occurs when ribosomes use the code carried by mRNA to produce a polypeptide/protein (happen in CYTOPLASM)

Question 14

what does the separation of transcription and translation allow?

Answer 14

the separation of thw two processes allows post-transcriptional modification of mRNA to occur in the nucleus (before translation happens). in prokeytoic cells there is no isolation, so mRNA can immediately come in contact ith ribosomes and initiate translation without modification. this reduces chance of errors from occuring in production of polypeptides. this compartmentalization allows greater cell efficiency.

Question 15

all eukaryotic cells posses organelles involved with…

Answer 15

1) energy production
2) biosynthesis
3) metabolism
4) degradation

Question 16

acinar cells

Answer 16

a type of pancreatic cell specialised in secretion of digestive enzymes. they’re essential to human life and have gretaly enlarged Golgi apparatus, ER, and granule storage comaprtments.

Question 17

benefits of compartmentalisation of lysosomes

Answer 17

lysosomes contain digestive enzymes that could severly damage the cell if not isolated by a membrane.

Question 18

process of endocytosis and formation of phagocytic vacuoles

Answer 18

1) entrapment
2) formation of phagocytic vacuole
3) fusion with lysosomes (allowing inactviation and digestion of the threat)
4) digestion

the phagotyic vacuole is a meains of protecting the cellular contents from potential damage when phagocytosis occurs, bringing in food particles or pathogens.

phagocytosis plays a key role in defending cells against invading pathogens.

Question 19

challenge of compartmentalisation

Answer 19

1) the cell must develop a mean of integrating ALL separate functions since each organelle carries out specific functions.
to accomplish this some organelles are connected in a functionla series, allwoing important chemical pathways to take place.
membrane pumps and carriers have evolved so that the products of one organelle can enter another and important reactions can occur.

Question 20

adaptions of the mitcohondria to sucessfully produce ATP energy by aerobic respiration

Answer 20

1) outer membrane: sepeartes its contents from the rest of the cell
2) matrix: cytomplasm-like subastance contaiing enzymes for first stages of respiration that take place in mitochondria (e.g. the link reaction and the Kreb’s cycle)
3) cristae: tubular regions surrounded by membranes that increase the surface area for reactions at the end of respiration (e.g. oxidative phosphorylation)
4) inner membrane: contains carrers and enzymes for final stages of respiration (e.g. electron trasnport chain and chemiosmosis)
5) space between the inner membrane and outer membrane: resevoir for hydrogen ions (protons) allowing a high concentration of protons

Question 21

adaptation of the cholorplast to conduct photosynthesis

Answer 21

1) extensive membrane surface area of the thylakoid: grater absorption of light by photosystems
2) small space (lumen) and low volumes of fluid within thylakoids: faster accumulation of protons to create concentration gradient
3) stroma region simialr to cytoplasm of the cell and mitochondrial matrix: provides region where enzymes for Calvin cycle can work
4) double outside membrane: isolates working parts and enzymes of chloroplast from surrounding cytoplasm

Question 22

respiration

Answer 22

glucose chemical bonds broken for ATP energy

overall equation for cellular respiration:
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy

Question 23

photosynthesis

Answer 23

chemical bonds made for carbon compounds.

overall equation for photosynthesis:
6CO2 + 12H2O + light energy –> C6H12O6 +6H2O + 6O2

occurs in animals reerred to as anotrophs (animals that make their own food)

Question 24

similarities between mitochondria and cholorplast structure

Answer 24

• both have extra outer membrane
• their own DNA
• both close in size to a prokaryotic cell

Question 25

features of the nucleus

Answer 25

1) nuclear envelope: a double membrane providing a area where DNA can carry out its functions without being affected by surrounding reactions. it also breaks down early on in cell division process (mitosis and meiosis) to allow movement of DNA strcutures.
2) nuclear membrane: has many pores that extend through both layers of the nuclear envelope. these pores allow ions and small molecules to diffuse between the nuclear material, nucleoplasm, and cytoplasm. pores can also control passage of mRNA, proteins, and RNA-protein complexes (often become ribosomes and produced in the nucleolus) in and out of the nucleus.
3) outer membrane of nuclear envelope: continuous with ER + shares functions with it
4) inner membrane of nuclear envelope: interacts with chromatin (inactive form of DNA) and also maintains nucleus shape

Question 26

ribosomes

Answer 26

made of proteins and RNA and has 2 subunits:
1) the larger subunit has two specialised bingdign sites (P site and A site)where molecuels carrying amino acids can attatch. these sites allow multiple amino acids to be bonded into highly specific proteins
2) smaller subunit has an mRNA binding site

eukaryotic ribosomes are located either:
1) attatched ot the ER 2) free floating in the cytoplasm

Question 27

free floating ribosomes

Answer 27

they produce proteins used within the cell. e.g. supporting the cytoskeleton, and laso used in nucleus, mitochondira and in otehr ogranelles not derived from the cell’s inner membrane system.

Question 28

membrane bound ribosomes

Answer 28

produce proteins transported through ER and often exported out of the cell. can produce secretory proteins sent to the Golgi apparatus where they’re packed for cellular exit (e.g. hormones and enzymes)

Question 29

Golgi apparatus (and its role in processing and secreting proteins)

Answer 29

• transport vesciles (fileld with proteins or lipids) are recieved on the cis side from either the right or smooth ER.
• as the protein or lipid move through the cisternae they’re modified to carry out specific function needed at the time.
• once modified product is packaged into a vesicle that depart on the trans side.
• often mdoficiation of a vesicle involves the attatchment of a signal chemical that directs the destination of the product
• some vesicles may beocme lysosomes wihtin the cell, others may turn into ER. many will combien with the plasma membrane and undergo exocytosis

Question 30

vesicles

Answer 30

small membrane-bound scs in which various substances are transported or stored in the cell
common vesicles:
* peroxisomomes: contain enzymes to break down fatty acids
* lysosomes: contain enzymes necesarry for cellualr digestion and for destroying defective or damaged organelles.
* transport vesicles: move molecules within the cell
* secretory vesicles, contain material to be excreted form the cell, such as neurotransmitters and hormones

Question 31

clathrins

Answer 31

proteins in cell membrane that anchor certain proteins to specific cites. important example if there presenece in plasma membrane in receptor-mediated exocytosis.

Question 32

receptor-mediated exocytosis

Answer 32

clathrins line coated pits, allwoing recptors to bind to specific molecules. whan an appopriate colelction og molecules occcurs in the lined pit, the pit deepends and will eventually seal off forming a vesicle. thsi process is highly specific where sealing off and the formation of vesicles occurs very rapidly.
different cells need different molecules thus they have specific recpetors on their surface.