IB Biology Paper I Practice Test #3

What structures are found in eukaryotes but not in prokaryotes? (As a clue for your exam in May, use the evolution of previous tests as a guide for how you study for this one. You will likely have a prokaryote vs. eukaryote question. Don't simply answer the question below and move on. Study further differences between them. For example, prokaryotes have a 70s ribosome. What size ribosomes do eukaryotes possess?)

Membrane proteins of mice cells are marked with green and membrane proteins of human cells were marked with red. The cells were fused together. What would be seen after two hours? (Hint: This is an easier question than it appears at first. How similar or different are cell membranes across eukaryotic species?)

Potassium channels exist in the axon of neurons. What is the function of a potassium channel? (See question #3 of the booklet on blackboard for a diagram of a potassium channel, but it isn't necessary if you remember how K+ moves through the membrane of an axon.)

What structure is labelled "X" in the protein diagram from question #3?

In the experiments of Meselson and Stahl, E. coli were grown for many generations in 15-N, and then for one generation in 14-N (a different isotope of N). What results for the DNA of the last generation showed that replication was semi-conservative?

In 1828, Friedrich Wohler artificially produced urea (an organic compound) by an internal rearrangement of the atoms of ammonium cyanate (an inorganic compound). What important principle did this experiment show?

What characteristic of hemoglobin allows it to be considered a protein with quaternary structure?

What type of fatty acid is shown in the diagram for question #8?

What type of bond is labelled "X" in the diagram of DNA shown for #9?

Question #10 shows different forms of a gene from two species--a mouse and a monkey. What term is used to describe alternative versions of a gene? (Hint: Pay less attention to the letters representing the gene and more attention to the hint in the question. Make sure you study what "loci" are for your exam in May.)

Rice has 24 chromosomes in diploid cells while humans have 46. What is a valid conclusion from these data?

The electron micrograph shows the chromosomes in one stage of meiosis. What do the arrows indicate? (For your exam in May, make sure you know when these structures form during meiosis.)

Huntington's disease is a neurological disorder caused by the repetition of the amino acid glutamine in the protein Huntingtin. The higher the number of repetitions of glutamine, the earlier the onset of the disease. What type of disease is it? (Hint: Glutamine is an amino acid translated from an mRNA codon, which is transcribed from DNA. Only two answer make sense, and one makes more sense than the other.)

Use the table of the genetic code for #14 to determine the codon for methionine (the start codon for all protein synthesis in all organisms).

What is a mesocosm? (You were supposed to build one of these in your first year of IB biology when you studied ecology. Read about them in your book.)

Which group of organisms converts carbon into a form that is available to primary consumers?

What is a consequence of a global temperature rise on arctic ecosystems?

The pentadactyl limbs of many vertebrates shown for #18 have similar structures. In the diagram, all of the organisms have a humerus, radius, and ulna bones. What hypothesis is currently accepted to account for the similarity in limbs?

What are the three domains of living organisms? (Hint: Are viruses living? So do we classify them? As your study hint for May, which domains are more closely related to each other, and what organic compound can be compared that allows us to make this inference. It's not DNA b/c it mutates relatively too often compared to this other compound?)

What can be deduced about Brachythoracids from the cladogram for question #20? (Note: There is no timeline on this cladogram.)

What is a similarity between arteries and capillaries?

What effect does HIV have on the immune system? (I didn't cover this in our lecture. I skipped it to save time, but you should refer to my immune system slides and the book about HIV.)

Observe the micrographs of alveoli for question #23. One is of emphysema and the other is a normal lung. What can be observed in the alveoli of a person suffering from emphysema? (Hint: We explored emphysema by counting the number of times a line crosses the walls of the alveoli of someone with the illness.)

What is the change in the oscilloscope occurring between X and Y of the diagram shown for #24?

Which response takes place when blood glucose levels are low?

In the Hershey and Chase experiment, what observation led to the conclusion that DNA was the genetic material?

Some regions of DNA do not code for proteins. What is coded for by some of these regions?

Where in the cell does the splicing of immature mRNA occur in eukaryotes?

A tRNA with anticodon CAG carries the amino acid valine. Which codon of mRNA will the tRNA join?

How does a competitive inhibitor interact with an enzyme?

In the diagram for #31, which arrow indicates how protons (H+) move to generate ATP directly?

The image shows an electron micrograph of a chloroplast. What is a function of X?

How does water travel up the xylem on a hot, sunny day?

In growing shoots, auxin is transported from the apex down the shoot. Proton pumps store energy in the form of a proton gradient and membrane potential, and then tap this energy source to allow the movement of auxin. What method of transport is this? (Hint: It's kind of like the absorption of glucose in the small intestine or the reabsorption of glucose back into the body from the kidney.)

Which compounds are required for the germination of seeds to occur? (As a study hint, you should not just answer this question. You should review what each compound does and refresh your memory as to which sugar plays a role in seed germination.)

In a species with a diploid number of 16, what will the number of chromosomes be in a daughter cell after division by mitosis or meiosis?

What causes genetic variation in gametes during meiosis?

The Rh+ antigen is found on the surface of red blood cells in people who are rhesus positive. A rhesus negative woman gives birth to a rhesus positive baby. What is a possible explanation for subsequent pregnancies triggering the immune response?

The diagram for question #39 shows a nephron of a kidney. Which labelled part is permeable to sodium but not water?

Which is the correct sequence of stages in fertilization?