Unit 1

Question 1

% body fluid in intracellular/extracellular space

Answer 1

1/3 extracellular

2/3 intracellular

Question 2

Higher in extracellular or intracellular fluid:

Amino acids, bicarbonate, chloride, fatty acids, glucose, magnesium, oxygen, phosphate, potassium, sodium

Answer 2

Intracellular - potassium, magnesium, phosphate

Extracellular - sodium, chloride, bicarbonate, oxygen, glucose, fatty acids, amino acids

Question 3

Formula for gain

Answer 3

Gain = Correction/Error

Question 4

Where are sphingolipids most numerous

Answer 4

Nerve cells

Question 5

Sphingolipid functions (3)

Answer 5

Protection from harmful environmental factors
Signal transmission
Adhesion site for extracellular proteins

Question 6

Functions of glycocalyx (4)

Answer 6

Negative charge - repels other negatively charged objects
Site of attachment
Receptors
Immune reactions

Question 7

Function of SER

Answer 7

Lipid synthesis

Question 8

Golgi function

Answer 8

Processing substances from ER

Forming lysosomes, secretory vesicles and cytoplasmic components

Question 9

Lysosome function

Answer 9

Intracellular digestive system - digest damaged cellular structures, food particles and bacteria

Question 10

Enzyme in lysosomes

Answer 10

Hydrolase

Question 11

Differences between peroxisomes and lysosomes

Answer 11

Formed by self replication or budding off SER (vs Golgi)
Contain oxidases (vs hydrolases)
Oxidases form hydrogen peroxide, acts in combination with catalase to oxidise otherwise poisonous substances
Major function to catabolise long chain fatty acids

Question 12

Mitochondria structure

Answer 12

2 lipid bilayer protein membranes - outer and inner
Inner folded - cristae - oxidative enzymes attached
Inner cavity filled with matrix - contains dissolved enzymes

Question 13

Where are mitochondria formed

Answer 13

Self replicative

Question 14

What is the nucleolus

Answer 14

An accumulation of large amounts of RNA and proteins

Question 15

How are lysosomes adapted to kill phagocytksed bacteria?

Answer 15

Lysozyme - dissolves cell wall
Lysoferrin - binds iron
Acid - pH 5 => activates hydrolases

Question 16

What organelle is responsible for glycogen breakdown

Answer 16

Endoplasmic reticulum

Question 17

What are the 2 main functions of the Golgi apparatus?

Answer 17

1 - additional processing of substances formed in the ER (by adding CHO and compacting)
2 - CHO synthesis (hyaluronic acid and chondroitin sulphate)

Question 18

ATP structure

Answer 18

Adenine - nitrogenous base
Ribose - pentose sugar
3 x phosphate radicals

Question 19

Where do the different stages of glucose metabolism occur in the cell and how much do they account for overall glucose metabolism?

Answer 19

Glycolysis - cytoplasm - 5%

CAC/Kreb’s cycle - mitochondria - 95%

Question 20

DNA components

Answer 20

Phosphoric acid
Deoxyribose
Nitrogenous base

Question 21

Purine bases

Answer 21

Adenine and guanine

Question 22

Pyrimidine bases

Answer 22

Thymine and cytosine

Question 23

DNA base pairing

Answer 23

A - T

G - C

Question 24

How many nucleotide pairs are in each full turn of the DNA helix?

Answer 24

10

Question 25

Define transcription and translation

Answer 25

Transcription - DNA => RNA | Translation - RNA => protein

Question 26

RNA components

Answer 26

Ribose Phosphoric acid Nitrogenous base

Question 27

RNA bases

Answer 27

Guanine, cytosine, adenine, uracil

Question 28

Describe the process of activation of RNA nucleotides

Answer 28

Activated by RNA polymerase - adds 2 phosphate radicals to each nucleotide to form triphosphates Last 2 phosphates combined by high energy phosphate bonds => large quantities of ATP energy made available to nucleotides

Question 29

What enzyme is responsible for RNA assembly

Answer 29

RNA polymerase

Question 30

What are the different types of RNA? | What are their functions?

Answer 30

1 - precursor messenger RNA - processed in the nucleus to form mature messenger RNA 2 - small nuclear RNA - directs splicing of pre-mRNA to form mRNA 3 - messenger RNA - carries genetic code to cytoplasm 4 - transfer RNA - transports activated amino acids to ribosomes 5 - ribosomal RNA - forms ribosomes 6 - micro RNAS - regulate gene transcription and translation

Question 31

Where are ribosomes formed?

Answer 31

Nucleolus

Question 32

How are miRNAs formed?

Answer 32

Primary precursor RNA - processed in cell nucleus by microprocessor complex to pre-miRNAs Pre-miRNA further processed in cytoplasm by dicer enzyme - helps assemble RNA-induced silencing complex and generated miRNA

Question 33

Where is the microprocessor complex found?

Answer 33

Nucleus

Question 34

Where is dicer enzyme found?

Answer 34

Cytoplasm

Question 35

How to miRNA regulate gene expression

Answer 35

Bind to complementary RNA and promote repression of translation or degradation of RNA

Question 36

What is small interfering/silencing RNA?

Answer 36

Short, double stranded RNA molecules that interfere with gene expression Normally synthetic

Question 37

Which enzyme forms peptide bonds during translation

Answer 37

Peptidyl transferase

Question 38

What are the stages of DNA replication?

Answer 38

1 - DNA helicase unzips DNA 2 - DNA primase generates RNA primer - binds at starting point of replication 3 - DNA polymerase adds nucleotides 4 - DNA ligase bonds nucleotides 5 - termination - exonuclease removes primers, replaced with bases. Exonuclease also proofreads

Question 39

What are Okazaki fragments?

Answer 39

Pieces of DNA between primers not yet bound to remainder of stand

Question 40

What is the function of topoisomerase?

Answer 40

Acts during DNA replication, prevents DNA in front of replicative fork becoming overwound

Question 41

What are histones? What is their function?

Answer 41

Small molecules of electropositivity. DNA helix coiled around. Regulate DNA activity, when DNA is tightly packaged cannot function as template for RNA formation or DNA replication

Question 42

What are the stages of mitosis?

Answer 42

Interphase - interval between mitosis. Towards the end centrioles form in cytoplasm. Before mitosis centrioles move apart and microtubules grow away from centrioles forming aster Prophase - chromosomes condense Prometaphase - micro tubular spines of the aster penetrate the nucleus and attach to chromatids at the centromere. Metaphase - asters move further apart Anaphase - chromatids pulled apart at the centromere Telophase - mitotic apparatus dissipates, new nuclear membrane forms and cell pinches in two

Question 43

What are telomeres?

Answer 43

Region of repetitive nucleotide sequences at the end of a chromatid - serve as protective caps

Question 44

Where/when is telomerase found?

Answer 44

Stem cells, germ cells, cancer cells

Question 45

Briefly, what is transcription?

Answer 45

DNA => RNA

Question 46

Briefly, what is translation?

Answer 46

RNA => Protein