Biology (DOST JLSS Reviewer)

This Biology Practice Test is comprised of 50 random questions from General Biology. It is comprised of questions from topics such as Cell/Cell Cycle/Cell Transport System; Energy Transformation; Organismal Biology; Genetics; and Evolution. Please read the questions carefully and choose the correct answer from the choices below. The correct answer will be marked green; otherwise, it will be marked red. Good luck!

Which of the following is true regarding plasmodesmata?

Plasmodesmata allow for neighboring plant cells to transport ions, water, and other substances.

Plasmodesmata are found in animal cells.

Plasmodesmata "pin" adjacent cells together, enabling tissues, like cardiac muscle, to stretch without breaking.

Plasmodesmata form when connexons align in adjacent cells to form a channel.

A mutation occurs in the chloroplasts of a lettuce plant, causing its thylakoid membranes to become more permeable to charged ions. How might this mutation affect the Calvin cycle?

There would be no change to the Calvin cycle.

More carbohydrates would be produced by the Calvin cycle.

Fewer carbohydrates would be produced by the Calvin cycle.

Huntington’s disease is a rare inherited disorder caused by an autosomal dominant allele of the huntingtin gene. As individuals with the disease age, their neurons degenerate at an accelerated rate compared to individuals without the disease.

Which of the following pedigrees shows a likely pattern of inheritance in a family with a history of Huntington’s disease?

Which of the following are components of adenosine triphospate (ATP)?

Deoxyribose, a cytosine base, and a triphosphate group

Ribose, a cytosine base, and a triphosphate group

Deoxyribose, an adenine base, and a triphosphate group

Ribose, an adenine base, and a triphosphate group.

Which of the following statements best describes eukaryote chromosomes compared to prokaryote chromosomes?

Prokaryotes generally have multiple linear chromosomes, while eukaryotes have a single-stranded circular chromosome.

Eukaryotes generally have multiple linear chromosomes, while prokaryotes have a single-stranded circular chromosome.

Prokaryotes typically have a single linear chromosome, while eukaryotes typically have multiple circular chromosomes.

Eukaryotes generally have a single linear chromosome, while prokaryotes have a multiple-strand chromosomes.

What is the relationship between anabolic and catabolic pathways?

Anabolic pathways create complex molecules using the energy from catabolic pathways.

Molecules broken down by anabolic pathways provides energy for catabolic pathways.

Anabolic and catabolic pathways are interchangeable.

Catabolic pathways synthesize complex molecules that are destroyed by anabolism.

Which of the following equations correctly summarizes the process of photosynthesis?

carbon dioxide + oxygen ⟶ water + glucose

carbon dioxide + water ⟶ glucose + oxygen

carbon dioxide + glucose ⟶ water + oxygen

glucose + oxygen ⟶ carbon dioxide + water

In natural selection, one variation which is present in ALL members of a population is a called a -

diversity

genotype

speciation

adaptation

The enzyme ptyalin helps digest carbohydrates, while the enzyme pepsin helps digest proteins. What prevents ptyalin and pepsin from digesting the same type of food?

They require a different number of molecules to react.

One is a protein and the other is a carbohydrate.

They have the same amino acids chain.

They have different shapes.

The fossil of Archaeopteryx represents the evidence of origin of:

reptiles from amphibians.

birds from reptiles.

mammals from birds.

mammals from reptiles.

How can substances be transported across a membrane against their concentration gradient?

The plasma membrane is permeable to all small molecules.

Some membrane proteins are ATP-dependent carrier molecules.

The plasma membrane is fully hydrophobic.

Some membrane proteins act as channels for specific molecules to enter the cell.

A gray wolf's sperm contains 39 chromosomes. He mates with a female gray wolf. How many chromosomes will there be in the resulting zygote?

19.5

156

Why is DNA important?

it's in everything

it serves as the blueprint for traits of all living things

it is very small and very complicated

because we eat it every day for energy

Which of the following molecules crosses through a semipermeable membrane during the process of osmosis?

Proteins

Glucose

Water

Sodium

Organisms in temperate zones are able to time their activities to cues given by the photoperiod, since:

All organisms need time to rest.

Light is a limiting factor.

All organisms have a biological clock.

Day length is always constant for a specific locality and season.

Which statement is true regarding catabolic pathways?

Catabolic pathways are used to construct macromolecules such as carbohydrates, lipids, and proteins.

Catabolic reactions consume energy.

Polymers are broken down into their monomers.

Molecules are synthesized using dehydration synthesis.

Which of the following is true regarding the proteins involved in facilitated diffusion?

Aquaporins are a type of carrier protein.

Channel and carrier proteins transport materials at different rates.

Ions such as sodium, potassium, and calcium can move across the membrane through the use of channel proteins.

Channel and carrier proteins allow molecules to diffuse passively against their concentration gradients.

Imarie uses a microscope to study different prokaryotic and eukaryotic organisms. Which of the following statements describes how the prokaryotic cells appear compared to the eukaryotic cells?

The prokaryotic cells have cell membranes, while the eukaryotic cells do not.

The prokaryotic cells have a nucleus, while the eukaryotic cells do not.

The prokaryotic cells have cytoplasm, and eukaryotic cells do not.

The prokaryotic cells are much smaller than the eukaryotic cells.

What level does the mice primarily eat in?

2nd trophic level

3rd trophic level

4th trophic level

1st trophic level

Which of the following is true about the kingdom Bacteria?

Some bacteria have a nucleus.

Bacteria have a cell wall.

Bacteria reproduce sexually.

Bacteria are not motile.

How does an enzyme affect the rate of a reaction?

It raises the activation energy of the reaction, decreasing the reaction rate.

It lowers the activation energy of the reaction, increasing the reaction rate.

It raises the activation energy of the reaction, increasing the reaction rate.

It lowers the activation energy of the reaction, decreasing the reaction rate.

A scientist views a unicellular organism called a euglena under a microscope. Based on the diagram, what type of organism is the euglena and why?

The euglena is eukaryotic, because it has a nucleus.

The euglena is prokaryotic, because it has mitochondria.

The euglena is prokaryotic, because it has a chloroplast.

The euglena is eukaryotic, because it has a flagellum.

The human body has 23 homologous pairs of chromosomes. How many chromosomes does a somatic cell have?

Fill in the blanks: Proteins are made of different ____________ which are arranged in different orders, or _________________.

amino acids, sequences

mRNA, bases

polymers, monomers

ribosomes, tRNAs

How is ATP hydrolysis used to power other cellular reactions?

It produces water which is used to fuel other reactions.

It acts as an enzymatic catalyst.

It is coupled with endergonic reactions.

It adds a phosphate to ADP.

A botanist is studying the genetics of a particular species of plant. She knows that one plant may contain hundreds of individual seeds, each of which is the result of a separate fertilization event. She determines that seed color is controlled by a single gene with two alleles. The dominant allele results in black seeds, and the recessive allele results in brown seeds.

In a follow-up experiment, the botanist crosses a homozygous dominant plant with a heterozygous plant.

Which of the following is the best prediction for the frequency of brown seeds that would result from this cross?

0.00

0.50

1.00

0.25

The Calvin cycle is considered light-independent because it can occur in darkness. However, most often the Calvin cycle takes place in sunlight. Which of the following likely explains why?

RuBP regeneration requires sunlight in order to occur and continue the Calvin cycle.

The enzymes involved in the Calvin cycle are unable to bind substrates in the dark.

The Calvin cycle requires ATP and NADPH, which require sunlight to be produced.

Sunlight is important in activating carbon fixation in the Calvin cycle.

Most toxins and poisons like cyanide, nerve gas etc. are non-competitive, irreversible inhibitors of key enzymes and are, therefore, lethal. Which type of molecular interaction is likely responsible for their irreversible binding with the enzyme molecules?

Covalent Bonding

Strong Ionic interactions

Van Der Waals Forces

Hydrogen Bonding

Which of the following are roles of amino acids at an enzyme's active site?

Preventing the substrate from entering the chemical reaction

Converting the enzyme to receive a different substrate

Changing the enzyme itself

Binding the substrate to the enzyme

A scientist hydrolyzes ATP in a laboratory test tube. He finds that about 3 times as much heat is released than when the same amount of ATP is hydrolyzed in a cell. What best explains the scientist's observation?

Cells are less efficient at producing heat.

ATP hydrolysis in a cell makes different products than in a test tube.

Cells often convert some of the energy from ATP hydrolysis into other usable forms.

Enzymes in cells use heat energy to catalyze reactions.

In animals, sexual reproduction depends on the production of gametes. Which of the following processes produces gametes in animals?

Fragmentation

Mitosis

Binary fission

Meiosis

A group of students are studying flower color inheritance in the garden pea plant (Pisum sativum). They obtain a purple-flowered pea plant of unknown ancestry, allow it to self-pollinate, and collect 60 6060 of its seeds. After planting the seeds, they observe the growth of 42 4242 purple-flowered plants and 18 1818 white-flowered plants.

Which of the following best explains the flower colors seen in the offspring?

The flower color changes as the plants mature.

White flower color is a trait recessive to purple flower color.

A somatic mutation in the flower color gene produced the white flower color.

Purple flowers and white flowers are codominant.

Which of the following best describes a difference between artificial and natural selection?

Only artificial selection leads to evolution.

Natural selection involves selective breeding while artificial selection does not.

Natural selection leads to lower fitness over time, while artificial selection improves fitness of the selected group.

Natural selection leads to greater fitness over time, while artificial selection has no (or sometimes a damaging) effect on fitness.

What type of microscope would be most effective for studying a living cell?

Scanning electron microscope

Transmission electron microscope

Magnifying glass

Light microscope

The U shaped pipe shown in the figure below is divided with a membrane that is only permeable to water. Which of the following best describes how water will flow through the membrane?

The water levels are already equal so water will not flow through the semipermeable membrane.

Water will flow from side A into side B.

Water will flow from side B into side A.

Which of the following statements is true regarding the energy source used in primary vs. secondary active transport?

Both primary and secondary active transport use an electrochemical gradient.

Primary active transport uses an electrochemical gradient, while secondary active transport uses chemical energy such as ATP.

Both primary and secondary active transport use chemical energy like ATP.

Primary active transport uses chemical energy such as ATP, while secondary active transport uses an electrochemical gradient.

Which of the following is an example of a homozygous dominant genotype?

A student is examining an onion root tip cell under a microscope. Based on her observations, the student proposes that the onion root tip cell has completed interphase and is now in the first phase of mitosis. Which of the following pieces of evidence would best support the student’s claim?

Discrete chromosomes are scattered throughout the cell’s nucleus.

The cell’s chromosomes are aligned across the metaphase plate.

Separated sister chromatids are being pulled towards opposite ends of the cell.

The cell’s DNA is dispersed within the nucleus as chromatin.

Which symbiotic relationship is described by one individual benefiting and the other being neither harmed nor benefited?

Mutualism

Commensalism

Parasitism

Competition

Which of the following molecules is used as "energy currency" for the cell?

Phosphate group

Water

ADP

ATP

Which of the following choices describes a function of the plasma membrane? Choose all answers that apply.

Receiving cell signals

Separating the interior of the cell and the exterior of the cell

Synthesizing proteins

Controlling the passage of various molecules

Ptyalin is an enzyme produced in the:

Pancreas

Thyroid glands

Salivary glands

Pituitary glands

Which of the following describes the common ancestor of all eukaryotes, but not the common ancestor of all organisms?

a single-celled organism with a flagellum, a circular chromosome, and a peptidoglycan cell wall

a single-celled organism with mRNA molecules, a cell membrane, and cytosol

a single-celled organism with double-stranded DNA, cytoplasm, and ribosomes

a single-celled organism with membrane-bound organelles, linear chromosomes, and spliceosomal introns

Which correctly places the stages of mitosis in order?

prophase, metaphase, anaphase, cytokinesis

metaphase, prophase, interphase, telophase

prophase, metaphase, anaphase, telophase

metaphase, prophase, interphase, telophase

Pepstatin binds to the enzyme pepsin. The substrate is still able to bind to the active site, but the reaction is blocked. What is this an example of?

Compartmentalization

Competitive inhibition

Noncompetitive inhibition

Allosteric activation

The living material comprising the bulk of a cell is called the:

Protoplasm

Genes

Chloroplast

Cytochrome

Several genes are responsible for preventing cells from dividing when conditions are not right. Two examples are tumor suppressor genes and proto-oncogenes. Which of the following accurately compares tumor suppressor genes and proto-oncogenes?

A person who has both tumor suppressor and proto-oncogenes will always develop cancer.

Proto-oncogenes code for growth factors, while tumor suppressor genes inhibit cell division of damaged cells.

When a proto-oncogene mutates, it becomes a tumor suppressor gene.

Both tumor suppressor and proto-oncogenes prevent the spread of cancer by targeting and destroying existing cancer cells.

What organelle is the site of photosynthesis in plants?

Mitochondria

Cytoplasm

Chloroplasts

Ribosomes

A genetic mutation causes a snake to have brown skin. After many generations, most of the snake population has the brown skin mutation. Which of the following most likely caused this change?

All the snakes in the area were infected with the mutation.

The other snakes changed their colors to mimic the brown snake.

The same mutation occurred in other snakes in response to environmental conditions.

Snakes with the brown skin mutation are able to survive and reproduce more successfully than snakes without it.

Which component of a nucleotide contains the information needed to make proteins?

deoxyribose sugar

base

phosphate

amino acid