TOPIC 4 PMT QUESTIONS (24 - 22)

4.1 DNA, GENES AND CHROMOSOMES

4.1 DNA, GENES AND CHROMSOMES

What is the ebst method to decrease the frequency of antibiotic resistant bacteria in populations (1)

Vaccinate more people to reach herd immunity

What does non overlapping mean for the genetic code (1)

Each base is only part of one codon

How does bacteria with a thicker capsule make it more likely to survive (2)

Phagocytes less likely to bind to murein

Reduced phagocytosis so more bacterial growth

4.2 DNA AND PROTEIN SYNTHESIS

4.2 DNA AND PROTEIN SYNTHESIS

Describe the role of haemoglobin in the loading, transport and unloading of oxygen (5)

Hb binds to oxygen in lungs

At high partial pressure of oxygen

Binding of one oxygen molcule makes binding of another oxygen easier

Oxyhaemolgbin transported in red blood cells

Hb unloads oxygen in respiring tissues

At low partial pressure of oxygen

How are amino acids joined together during translation (1)

With the use of ATP

What is an organelle visible with TEM that is invisible with an optical micrscope (1)

Ribsomes

What are two biological molecules that can be coded for by a gene (2)

Pre mRNA

rRNA

tRNA

Give two types of molecules that ribosomes are made from (2)

Protein

rRNA

What does DNA have that RNA doesnt (nichce) (1)

Hydrogen bonds

Define a gene (1)

A sequence of DNA bases that codes for a polypeptide

How did PNA affect transcription by binding to the DNA (2)

PNA forms base pairs with DNA

Preventing RNA nucleotides from binding

Descrbibe the role of ATP in the process of translation in protein synthesis

ATP provides energy

So peptide bonds form between amino acids

4.3 GENETIC DIVERSITY VIA MUTATION

4.3 GENETIC DIVERSITY VIA MUTATION

Name the type of chromosome mutation that would result in an extra chromsome and what happens (2)

Non disjunction

The chromatids fail to separate

Why could all body cells have an extra chromsome (2)

Extra chromsome in gamete

Body cells produced via mitosis so all cells will be replicated with extra chromsome

How are cells with different numbers of chromsomes produced in mosaic trisomy (1)

Cells with extra chromsome are produced from cells with the mutation

Why does a hole in the septum cause a higher blood pressure in the lungs (2)

More blood moves from the left ventricle to right (due to thicker muscle in left ventricle)

Greater VOLUME of blood goes to lungs instead of rest of body

In rice question. what did both populations have variation due to other than independent segreagation (1)

Random fertilisation of gametes

Wat does the random fertilisation of gametes produce (1)

New combinations of alleles

How does the process of meiosis result in haploid cells (4)

DNA replication

Two nuclear divisions

Separation of homologous chromsomes (1st division)

Separation of sister chromatids (2nd division)

Produces 4 haploid cells

What is the answer for the number of different arrangements of chromosomes question that you got 16 for? (2 marks)

18

4.4 GENETIC DIVERSITY AND ADAPTATION

4.4 GENETIC DIVERSITY AND ADAPTATION

How to make 5cm cubed of 60% conc using distilled water and undiluted disinfectant

Add 3cm3 of disinfectant and 2cm3 of distilled water

What 2 things do bile salts do (2)

Emulsify lipids / fats

Form micelles

How does natural selection lead to all mammals in pop being able to produce CEL (4)

Random mutation results in new allele

Those with new allele able to digest tryglycerides

Those with CEL allele more likely to survive and reproduce

Directional selection leads to an increase in frequency of allele in population

Define a population

A population is a group of individuals of the same species that live in a specific geographic and are capable of interbreeding.

Use knowlegde of natural selection to explain why most of the human population in Africa are resistant to malaria (4)

A random mutation produced an allele

Those with the allele likely to survive malaria

So more likely to reproduce and pass on the allele

Over time, the frequency of the allele increases in the pop

What is the answer fot the NOVOBIOCIN dilution question

9 × 10⁸

Suggest two reasons why the bacteria were able to grow in the culture ocontaining chloramphenicol (an antibiotic) (2)

Conc of antibiotic was too low to kill all bacteria

Contamination with other resistant bacteria

Why might the number of E coli bacteria have decreased if the student had NOT used a sterilied pipette (2)

Different bacteria introduced

These bacteria use up space

What is the correct answer for the dillution of 3cm3 of culture with 12cm3 of water

480000 per mm3

What would the null hypothesis be for the guppy investigation (1)

The presence of stones has no effect on their behaviour

What type of selection did the scientists test when putting the predators in the guppy tank (1)

Directional

Why does the mean number of spots reduce for the guppies after predators introduced (3)

Fish with more spots less likely to survive and reproduce

Alleles for more spots less likely to be passed on

Frequency of (more) spots alleles decreases in pop

How does the use of antibiotics lead to antibiotic resistant strains of bacteria becoming more common causes of infection (3)

Some bacteria have a random mutation that causes them to have an allele for resistance

These resistant bacteria survive and reproduce

So higher frequency of allele in the population

4.5 SPECIES AND TAXONOMY

4.5 SPECIES AND TAXONOMY

What could have been done to the frog populations to increase number of mating calls

Add sexually active females

How can scientists obtain a reliable data for mean length of every fish filament

Random samples

Use a large sample size (>10)

Suggest why several bacterial species in recent years have been renamed

Use of EM with greater resolution

Describe how organisms are grouped in a phylogenetic classification system (2)

Put into a hierarchy of groups with NO overlaps

Grouped according to evolutionary origins

What is a method that a scientist can use to identify a species

Comparare amino acid sequences

4.6 BIODIVERSITY WITHIN A COMMUNITY

4.6 BIODIVERISTY WITHIN A COMMUNITY

What is a method that can be used for finding data about plants in a field (5)

Divide area into squares

Obtain random coords using computer

Use same method of measurement each time

Repeat many times

Find mean of data

Why is it not possible to extrapolate for the number of bird species recorded breeding each year beyond 1979

Not a linear relationship

What is succession

The process by which ecosystems change over time due to environmental changes

What is DNA genome sequencing

Genome DNA sequencing is the process of determining the exact order of nucleotides (A, T, C, G) in an organism’s DNA, revealing its complete genetic blueprint.

In recent years, our knowledge of prokaryotic biodiversity in the soil has increased, suggest why (2)

DNA genome sequencing now used

Rather than just recording observable characteristics

What does a high species richness but a low index of diversity mean

Lots of different species but low numbers for each species