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How do fat-soluble compounds generally enter a cell?

By diffusion over the cell membrane.

The bases in a DNA double helix are arranged opposite to each other and linked via H-bonds. With how many H-bonds is thymine linked to which partner base in a DNA chain?

Thymine and adenine are linked with 2 H-bonds.

What is a genetic locus?

The site of a gene on a chromosome.

What is heterochromatin?

Tightly packed chromatin.

What is an important function of the cap structure of mature mRNA?

Protection against 5'-exonucleases.

What is the role of enzymes called amino acyl-tRNA synthetases in translation?

They attach amino acids to tRNA.

Which process enhances the efficiency of protein synthesis in the cell?

Formation of polyribosomal complexes.

Hydrochloric acid is a strong acid. What is the pH of a 0.1M HCL solution in water?

1

Which solution acts as a buffer?

1) 25 mL 0.1M of the strong acid HF.

2) 25 mL 0.1M of the HCL mixed with 25 mL 0.1M NaOH.

3) 25 mL 0.1M of the weak base NH3 mixed with 12.5 mL 0.1M HCL.

4) 25 mL 0.1M NaF.

3

Which cell organel contains digestive enzymes required to degrade defect cell organelles?

Lysosomes.

What is the main function of the cytoskeleton?

To maintain cell shape and enhance resistance to mechanical deformation.

What is the destination of proteins that are synthesized without a sorting signal?

The cytosol.

What are the most abundant molecules in the cell membrane?

Phospholipids.

I-cell disease is a severe type of lysosomal storage disease that results from a defective phosphotransferase. What is the function of this phosphotransferase?

This enzyme transfers phosphate to mannose residues on specific proteins in the Golgi apparatus.

Which molecule is used in an anaerobic environment to produce energy and lactate?

Pyruvate.

Where does the electron transport chain take place?

At the mitochondrial inner membrane.

To which molecule is oxygen reduced in complex IV of the electron transport chain?

H2O.

Which type of cells shows intercalated disks as a typical characteristic?

Cardiac muscle cells.

A histological section has been stained and is studied under a light miscroscope. You are asked to identify a capillary with erythrocytes.

Which characteristic of erythrocytes will be useful to identify them in the section?

Absence of nucleus.

There are several different types of epithelia. Their names are based on cell shape and the number of cell layers. 

What is the best definition of a simple, cuboid epithelium?

A single layer of square-like cells.

What is autocrine cell signaling?

Signalling from a secreted substance by a cell leading to its own activation.

How do gap junctions make electrical coupling between cells possible?

Ions, such as calcium are being passed between cells.

What is the function of the protein PKC?

A protein that phosphorylates other proteins.

2 DNA sequences of the same gene in 2 different tissues.

Normal tissue:  GGC TGA CCA GGT CGA

Tumour tissue: GGC ATG ACC AGG TCG

What type of mutation is this?

Frameshift mutation.

A plant that has purple flowers is crossed with one that has white flowers. The offspring were 1/4 white and 3/4 purple. 

What were the genotypes of the parents?

Pp x Pp

What do the e-value and its size in a Blast output mean?

The lower the e-value, the better the hit.

What is the best strategy to find evolutionary distant family members of a protein coding gene?

Blast the protein sequence encoded by the gene against a protein database.

The Hardy-Weinberg theory states that for a gene with 2 possible alleles, the genotypes will be distributed according to the formula: 1=p^2+q^2+2pq.

What will be the formula if the gene has 3 possible alleles (p, q and r)?

1=p^2+q^2+r^2+2pq+2pr+2qr.

According to the evolution theory of Darwin, why did a specific species of birds develop larger beaks than other birds?

Some members of the ancestor population had larger beaks than others. Larger beaks were an advantage and increased the chance of survival and reproduction. The number of larger-beaked birds thus increased in frequency compared to smaller-beaked birds.

A technician wants to prepare a stock solution of 50mM of a compound that has a molecular weight of 100 g/mol.

How much of this compound does he/she have to weigh to make 10 mL of this stock solution?

0.05 gram.

A technician needs to dilute a stock solution of 4.786 g/L PBS in order to generate a 200 uM solution. The molecular weight of PBS is 239.3 g/mol.

What is the dilution factor?

100

A calibration line for vitamin C can be established by measuring the absorption of a number of vitamin C solutions with various concentrations. The results are represented in a graph with the absorption plotted on the y-axis and the vitamin C concentration on the x-axis.

What does the extinction coefficient in the diagram represent?

The slope of the curve.