Practice Paper 1A (HL IB Biology)

No viral protein enters the infected bacterial cells.

DNA has a greater mass than protein.

Around 80 % of the viral DNA enters the infected bacterial cells.

Most proteins are separated from the bacterial cells by the blending process.

There are so many different theories of how the first cells originated that it is impossible to make sense of all the conflicting information. 

It is impossible to know the conditions on early Earth and so it is impossible to replicate any of those conditions experimentally. 

The current scientific equipment that exists is not able to withstand the temperature and pressure conditions of early Earth and so the correct conditions cannot be replicated experimentally. 

Early cells did not fossilise well, making it difficult to know their exact nature or confirm hypotheses about their formation.

100 µm

50 µm

10 µm

0.5 mm

The viral DNA produces proteins that suppress the immune response, resulting in persistent virion production.

A repressor protein coded by the viral DNA prevents transcription and translation.

The host cell lacks the necessary enzymes for viral replication, forcing the virus to remain dormant until external factors activate its DNA.

Viral nucleic acid disrupts host cell reproduction, preventing cell division until lytic triggers occur.

Lepidoptera

Odonata

Coleoptera

Hemiptera

1. Human
2. Chicken
3. Fruit fly
4. Yeast
5. Mouse
6. Rat

1. Human
2. Rat
3. Mouse
4. Fruit fly
5. Yeast
6. Chicken

1. Human
2. Mouse
3. Rat
4. Chicken
5. Fruit fly
6. Yeast

1. Human
2. Yeast
3. Fruit fly
4. Chicken
5. Rat
6. Mouse

They show the complete transition between fish and four-legged land animals.

They show that species change to become better adapted to their environment.

They strengthen the evidence for species change over time provided by the rest of the fossil record.

They show that limbs are always advantageous over fins.

I only

I and II only

II and III only

I, II and III

An ester bond forms between the -COOH group of three fatty acids and an -OH group on one glycerol molecule, along with the release of three molecules of water

An ester bond forms between the -COOH group of three fatty acids and a -CH group on one glycerol molecule, along with the release of three molecules of water

An ester bond forms between the -COOH group of three fatty acids and an -OH group on one glycerol molecule, along with the absorption of three molecules of water

An ester bond forms between the -COOH group of three fatty acids and a -CH group on one glycerol molecule, along with the absorption of three molecules of water

Only the 20 amino acids existed when life began, so all life now uses them.

All organisms share a common ancestor, so the link between the genetic code and amino acids sequences is already fixed. 

Polypeptide chains join together to increase the range of possible functions that they can carry out

20 amino acids is more than enough to give a huge, almost infinite range of characteristics for all life. 

Groups of protein and phospholipid molecules in the cell surface membrane are attached to each other and move together

Only the protein molecules in the outer layer of the cell surface membrane can move freely between phospholipid molecules

All protein molecules in the cell surface membrane are fixed to structures within the cell, but phospholipid molecules move freely between them

Protein molecules in the outer layer of the cell surface membrane, and those which span the bilayer, can move freely between phospholipid molecules

A large surface area of thylakoid membranes with photosystems.

A large volume of fluid inside thylakoids.

Compartmentalisation of enzymes and substrates of the Calvin cycle in the stroma.

Chloroplast DNA that contains genes which code for some of the proteins and enzymes used in photosynthesis.

They can differentiate into specialised cells

They can produce chemicals that destroy viruses

They can form gametes when they divide by mitosis

They have chromosomes that are suitable for gene transfer

The active loading of sucrose into phloem sieve tubes near the fruit will create a hydrostatic pressure gradient that will facilitate mass flow between the leaves and fruit.

The movement of water molecules in the phloem sieve tubes from the leaves to the fruit will contribute to the hydrostatic pressure gradient between them.

The movement of organic compounds into the phloem sieve tubes near leaves will increase the hydrostatic pressure in the sieve tubes and create a pressure gradient between leaves and fruit.

The unloading of organic compounds from the phloem sieve tubes at the fruit will increase the osmolarity of the sieve tubes and create a hydrostatic pressure gradient between the leaves and fruit.

Biome distribution is affected primarily by biotic factors.

For any given temperature and rainfall pattern there are a range of ecosystem types that can develop.

A tropical rainforest biome will have high annual rainfall and low levels of biodiversity.

Average temperatures and rainfall patterns are significant factors in determining the development of a biome.

I only

I and II only

I and III only

II and III only

This is an anabolic reaction that releases energy. Large, complex molecules are broken down into smaller, simpler ones during hydrolysis reactions.

This is a catabolic reaction that releases energy. Large, complex molecules are broken down into smaller, simpler ones during hydrolysis reactions.

This is an anabolic reaction that requires an input of energy. Large, complex molecules are formed from smaller, simpler ones during condensation reactions.

This is an catabolic reaction that requires an input of energy. Large, complex molecules are formed from smaller, simpler ones during condensation reactions.

17

34

36

18

White light gives the optimal conditions for photosynthesis.

There is a linear relationship between wavelength of light and plant growth.

Red light enhances plant growth.

There is no correlation between total biomass and plant height.

Calcium ion channels open and calcium moves across the postsynaptic membrane triggering an action potential.

Positively charged ions diffuse through ion channels across the membrane causing a change in voltage across the plasma membrane.

An action potential is triggered when a threshold level of acetylcholine receptors are occupied.

Sodium ions are actively pumped across the membrane to initiate an action potential in the postsynaptic neurone.

6

60

12

7

The difference between an estimated population size and a true population size.

The process of counting small samples of a population that will represent a whole population.

When some members of a population are more likely to be counted than others.

When positions of the sampling points are not selected at random.

Breaking of hydrogen bonds.

DNA polymerase forms an enzyme-substrate complex with free nucleotides. 

Formation of new covalent bonds between nucleotides.

Formation of new glycosidic bonds between deoxyribose molecules. 

Only tumour cells contain mutations

Tumour cells do not undergo cytokinesis

Tumour cells have a shorter interphase

Tumour cells do not have metaphase

Adding a methyl group causes the DNA to be less tightly wrapped

Adding a methyl group deactivates the gene

Adding a methyl group causes the DNA to be more tightly wrapped

Adding a methyl group helps maintain a positive charge

Build up due to the lack of ovulation.

Be shed too often.

Build up due to the lack of menstruation.

Be shed during ovulation.

0.44

0.28

0.14

0.07

Cell damage might occur due to osmosis.

Cells with a higher osmolarity than their surroundings will lose water and shrink.

Cells with a higher osmolarity than their surroundings will gain water and could burst.

Cells with a lower osmolarity than their surroundings will lose water and shrink.

Finches adapt to drought years by developing larger beaks, passing on the characteristic to their offspring, and leading to an increase in average beak size.

Average finch beak size increases during years of drought and decreases during wet years.

Average beak size increased from 9.5 mm in 1976 to 9.9 mm in 1977, before slowly decreasing to 9.7 mm by 1979.

Finches with larger beaks have an advantage when competing for food in drought years, and are therefore more likely to survive and pass on their alleles, leading to an increase in average beak size.