B2W7 (DONE) Flashcards by Phoenix Hui

What are cells?

The basic unit of life

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What do organelles have?

Specific functions

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Function of cell membrane

Regulates the entry and exit of substances

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Structure of cell membrane

Phospholipid bilayer with integral/peripheral proteins

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Structure of lysosome

Small membrane-bound organelles

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Function of lysosome

(+ elaborate)

Packet of enzymes that break down materials in a cell

(materials: macromolecules and broken down organelles)

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Lysosomes fuse with (a) and passed into (b) to become (c)

(a) Food vacuoles
(b) cytosol
(c) nutrients of the cell

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Lysosomal enzymes work best at what pH?

pH 5

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How do lysosomal enzymes maintain their low pH?

Proteins in lysosomal membrane pump H+ ions from cytosol to lysosome

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Self-destruction of cells is called

Apoptosis

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Apoptosis

Definition

Self-destruction of cells

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Structure of vacuole

Small and membrane-bound

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Function of vacuole

To store water, nutrients and waste

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Structure of mitochondria

Double membrane (envelope)

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Function of mitochondria

To convert food energy into ATP

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Structure of DNA

Double helix made up of nucleotides, containing the sugar-phosphate backbone and nitrogenous bases

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Function of DNA

Genetic material of life

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Structure of nucleoplasm

Amorphous fluid containing proteins, RNA, ribonucleotides and small molecules

Amorphous: without clearly defined shape

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Function of nucleoplasm

Contains fibrous chromatin

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Structure of rough ER

Sheet-like with ribosomes

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Function of rough ER

Site of protein synthesis

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What type of cells are rough ER prominent in?

Cells with extensive protein synthesis

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Structure of ribosomes

(size and shape)

Small and circular

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Function of ribosomes

Makes proteins

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Structure of cytoplasm

Includes all fluid and organelles except nucleus

Function of cytoplasm

Holds cytosol and organelles

Types of cytoskeleton

Actin filaments and microtubules

Function of cytoskeleton

Provides structure and support to the cell

Function of actin filaments

Change shape of cell

Function of microtubules

Movement of organelles and vesicles

Cell movement is (a) and (b)

(a) Polarised (b) Directional

Structure of Golgi Apparatus

Made of 4-6 layers of cisternae, pancake-shaped

Function of Golgi Apparatus

Packages, labels and ships proteins out of the cell

Steps undertaken by Golgi Apparatus | (for proteins)

Modification -> Processing -> Sorting and localisation

Protein modification

Addition of phosphates, fatty acids and sugars

Protein processing

Cleavage of peptides leads to activated proteins

Structure of smooth ER

Tubular without ribosomes

Function of smooth ER

To synthesise lipids

What types of cells are smooth ER prominent in?

Cells which undergo intensive lipid and drug metabolism

Function of nucleolus

Produces RNA which is used to make proteins

Structure of nucleus

Double-membrane bound

Function of nucleus

The control centre and regulates DNA and RNA

Structure of nucleus | (size and shape)

Large and spherical

Diameter of nucleus

6 um

% of cell occupied by nucleus

10% by volume

Function of nuclear envelope

Regulates what enters and exits the nucleus

Components of the nucleus

* Nucleolus * Nuclear pores * Nuclear envelope * Nucleoplasm

Structure of centriole

Tubules

Function of centriole

Divides the cell during cell division

Functions of ER | (4)

* Detoxification of drugs * Glycosylation of proteins * Translocation of proteins * Assembly of lipid bilayer

Route of protein-containing vesicle

Rough ER -> Smooth ER -> Golgi Apparatus

1 in (a) children will develop mitochondrial disease by the age of 10

4000

Stage I of oxidative metabolism

Large molecules broken down into smaller subunits

Stage II of oxidative metabolism

Small subunits modified into a few key molecules which play a central role in metabolism

Stage III of oxidative metabolism

Oxidation to produce ATP

Example of apoptosis

Loss of webbing between fingers during fetal development

Polar groups of phospholipid include:

* Choline * Phosphate * Glycerol

Formations of phospholipids

* Bilayer * Micelle * Liposome

Structure of cholesterol

* Polar head group * Steroid ring structure * Non-polar hydrocarbon tail

Addition of cholesterol causes such changes to the membrane:

* Lower fluidity * Packs more tightly * Lower flexibility

Structure and function of membrane proteins

TRACIE

T of TRACIE | (+ elab)

Transport | Protein channels and protein pumps

R of TRACIE

Receptors | Peptide based hormones (insulin)

A of TRACIE

Anchorage | Cytoskeleton attachments and extracellular matrix

C of TRACIE

Cell recognition | Antigens

I of TRACIE

Intracellular joinings | Tight junctions and plasmodesmata

E of TRACIE

Enzymatic activity | Metabolic pathways

Mechanism for movement of large molecules

Vesiculation

Types of vesiculation

Endocytosis, exocytosis

Types of endocytosis

Pinocytosis, phagocytosis

Mechanism for movement of small molecules

* Simple diffusion * Facilitated diffusion * Active transport

Exocytosis may be...

Constitutive (continuous) or regulated (triggered by receptors)

Bilayers are freely permeable to...

Gases, small uncharged polar molecules

Bilayers are impermeable to...

Ions, large uncharged polar molecules and charged polar molecules

Example of large uncharged polar molecules

Glucose, fructose

Examples of charged polar molecules

Amino acids, ATP, proteins, etc.

Facilitated diffusion exhibits (a)

(a) Saturation kinetics

Facilitated diffusion is susceptible to...

Competitive and non-competitive inhibition

Types of transport proteins for facilitated diffusion

Carriers/ channels

Channel proteins form (a) and usually allow (b) to pass through

(a) water-filled pores (b) ions

Active transport is mediated by (a) coupled to (b)

(a) carrier proteins (b) an energy source

2 main families of active transport proteins

1. P class transporters (ion pumps) 2. ABC transporters

Digitalis act on (a) by specifically (b) across the plasma membrane

(a) heart muscle cells (b) blocking ion transport

Drugs may be ineffective because...

Mutidrug (MDR) transporters pump drugs out of cells

When MDR is over-expressed in cancer cells...

It can make them simultaneously resistant to a variety of chemically unrelated cytotoxic drugs

Symptoms of mitochondrial disease

* Poor growth * Muscle weakness and pain * Vision and/or hearing problems * Learning disorders * Heart, liver and kidney problems * Diabetes * Lactate build-up * GI problems

Valproate levels too high means...

Valproate toxicity with symptoms of low blood pressure, high blood rate and respiratory depression

B2W7 (DONE) Flashcards

(87 cards)