BCH 201 Introduction to Biochemistry

Question 1

What is a cell?

Answer 1

The structural and functional unit of a living organism

Question 2

Diameter of eukaryotic cells

Answer 2

5-100 micrometers

Question 3

The cell can be divided into

Answer 3

Plasma membrane
Cytoplasm
Sub cellular organelles

Question 4

Discuss the cell membrane

Answer 4

It defines the periphery of the cell and separates the cell contents for the surrounding environment

It is made of a lipid bilayer, embedded with proteins (fluid mosaic model, Nicholson and singer) and a hydrophilic exterior and hydrophobic core

It has a highly selectively permeable membrane to regulate entry and exit of materials e.g membrane transport proteins regulate the influx and efflux of ions and molecules across the membrane

It also contains enzymes involved in metabolism

Question 5

Discuss the cytoplasm

Answer 5

This is the internal volume of the cell enclosed by the plasma membrane, consisting of aqueous sol. (cystol) and suspended organelles

It’s also contains organic and inorganic molecules, ions enzymes and metabolites

Question 6

The_and_are solitary whilst other organelles are numerous

Answer 6

Nucleus and Golgi apparatus

Question 7

Which mammalian cell does not contain a nucleus?

Answer 7

Red blood cell

Question 8

Functions of the nucleus

Answer 8

The most important organelle

Where DNA and genetic material is stored. The DNA consists of the full set of genes of the organism

Consists of a well-defined membrane called the nuclear envelope

A light portion of the nucleus, the nucleolus, is where RNA synthesis (transcription)

DNA replication occurs in the nucleus

Question 9

Functions of ER

Answer 9

This is a network of interconnecting membranes enclosing channels or cisternae

Question 10

Functions of smooth ER

Answer 10

Synthesis of complex lipids and steroids

Question 11

Function of rough ER

Answer 11

Consists of ribosomes where proteins are synthesized
It is also involved in drug detoxification

Question 12

Function of mitochondria

Answer 12

spherical, oval, rod-shaped body
power house of the cell where energy is released from the oxidation of food and stored as ATP for metabolic processes
double membrane, inner is folded into cisternae and contains enzymes of the ETC
cytochrome p450 system in mitochondria is involved in steroid synthesis
mitochondria also consists of DNA

Question 13

difference between genomic and organellar DNA

Answer 13

genomic dna is in the nucleus, double stranded, helical in shape
orgnellar dna is in the mitochondria, double stranded and circular in shape

Question 14

function of lysosomes

Answer 14

tiny organelles which digest foreign particles
Enzymes in lysosomes cause tissue damage

Question 15

function of golgi complex

Answer 15

network of flat smooth, membrane and vesicles
It is involved in sorting, packaging, maturation and release of already synthesized protein

Question 16

types of protein filament

Answer 16

actin-filament
microtubules filament
intermediate filament

Question 17

What are marker enzymes? Give examples

Answer 17

Enzymes that are specific to the organelle and are found in them only
Examples: Glucose-6 phosphate is found in microsome and lactic dehydrogenase is found in the cytoplasm

Question 18

function of the capsule in prokaryotes

Answer 18

it is gelatinous in nature and may be a polysaccharide or hyaluronic
the capsule is antigenic and antiphagocytic, it determines the virulence of many bacteria

Question 19

What is virulence?

Answer 19

Virulence is a pathogen’s or microorganism’s ability to cause damage to a host

Question 20

Function of flagella

Answer 20

proteinous extrusions through the cell wall, arising from the cytoplasm
they serve as organelles of motility and are also antigenic

Question 21

function of fimbriae or pili

Answer 21

Hair-like filaments and are also antigenic
Fimbriae are responsible for attachment of bacteria to specific receptors of human cell