Unit 1 Flashcards
% body fluid in intracellular/extracellular space
1/3 extracellular
2/3 intracellular
Higher in extracellular or intracellular fluid:
Amino acids, bicarbonate, chloride, fatty acids, glucose, magnesium, oxygen, phosphate, potassium, sodium
Intracellular - potassium, magnesium, phosphate
Extracellular - sodium, chloride, bicarbonate, oxygen, glucose, fatty acids, amino acids
Formula for gain
Gain = Correction/Error
Where are sphingolipids most numerous
Nerve cells
Sphingolipid functions (3)
Protection from harmful environmental factors
Signal transmission
Adhesion site for extracellular proteins
Functions of glycocalyx (4)
Negative charge - repels other negatively charged objects
Site of attachment
Receptors
Immune reactions
Function of SER
Lipid synthesis
Golgi function
Processing substances from ER
Forming lysosomes, secretory vesicles and cytoplasmic components
Lysosome function
Intracellular digestive system - digest damaged cellular structures, food particles and bacteria
Enzyme in lysosomes
Hydrolase
Differences between peroxisomes and lysosomes
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
Mitochondria structure
2 lipid bilayer protein membranes - outer and inner
Inner folded - cristae - oxidative enzymes attached
Inner cavity filled with matrix - contains dissolved enzymes
Where are mitochondria formed
Self replicative
What is the nucleolus
An accumulation of large amounts of RNA and proteins
How are lysosomes adapted to kill phagocytksed bacteria?
Lysozyme - dissolves cell wall
Lysoferrin - binds iron
Acid - pH 5 => activates hydrolases
What organelle is responsible for glycogen breakdown
Endoplasmic reticulum
What are the 2 main functions of the Golgi apparatus?
1 - additional processing of substances formed in the ER (by adding CHO and compacting)
2 - CHO synthesis (hyaluronic acid and chondroitin sulphate)
ATP structure
Adenine - nitrogenous base
Ribose - pentose sugar
3 x phosphate radicals
Where do the different stages of glucose metabolism occur in the cell and how much do they account for overall glucose metabolism?
Glycolysis - cytoplasm - 5%
CAC/Kreb’s cycle - mitochondria - 95%
DNA components
Phosphoric acid
Deoxyribose
Nitrogenous base
Purine bases
Adenine and guanine
Pyrimidine bases
Thymine and cytosine
DNA base pairing
A - T
G - C
How many nucleotide pairs are in each full turn of the DNA helix?
10
Define transcription and translation
Transcription - DNA => RNA
Translation - RNA => protein
RNA components
Ribose
Phosphoric acid
Nitrogenous base
RNA bases
Guanine, cytosine, adenine, uracil
Describe the process of activation of RNA nucleotides
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
What enzyme is responsible for RNA assembly
RNA polymerase
What are the different types of RNA?
What are their functions?
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
Where are ribosomes formed?
Nucleolus
How are miRNAs formed?
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
Where is the microprocessor complex found?
Nucleus
Where is dicer enzyme found?
Cytoplasm
How to miRNA regulate gene expression
Bind to complementary RNA and promote repression of translation or degradation of RNA
What is small interfering/silencing RNA?
Short, double stranded RNA molecules that interfere with gene expression
Normally synthetic
Which enzyme forms peptide bonds during translation
Peptidyl transferase
What are the stages of DNA replication?
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
What are Okazaki fragments?
Pieces of DNA between primers not yet bound to remainder of stand
What is the function of topoisomerase?
Acts during DNA replication, prevents DNA in front of replicative fork becoming overwound
What are histones? What is their function?
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
What are the stages of mitosis?
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
What are telomeres?
Region of repetitive nucleotide sequences at the end of a chromatid - serve as protective caps
Where/when is telomerase found?
Stem cells, germ cells, cancer cells
Briefly, what is transcription?
DNA => RNA
Briefly, what is translation?
RNA => Protein
