AP Biology : AP Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #151 : Dna, Rna, And Proteins

What type of chemical bonds are involved when codons bond to anticodons in translation?

Possible Answers:

Amide linkages

Ionic bonds

Phosphodiester bonds

Hydrogen bonds

Disulfide bonds

Correct answer:

Hydrogen bonds

Explanation:

The bonding of a codon to its anticodon is accomplished through the use of hydrogen bonds. Hydrogen bonds are weak bonds; therefore, amino acids are easily dissociated from their corresponding transfer RNA once delivered to the ribosome for translation. Hydrogen bonds are also responsible for connecting the bases of complementary strands of DNA which results in its double helix.

Example Question #152 : Dna, Rna, And Proteins

Proteins are polymers of __________.

Possible Answers:

amino acids

nucleotides

glucose

fatty acids

Correct answer:

amino acids

Explanation:

Proteins are polymers of amino acids, which have an amino group, carboxyl group, and a side chain known as an R-group. Nucleotides make up DNA and RNA. Glucose is a carbohydrate monomer and make up starches, cellulose, and glycogen. Fatty acids are components of lipids.

Example Question #15 : Understanding Amino Acids

What is the one element that proteins have that carbohydrates and lipids do not have?

Possible Answers:

Hydrogen

Oxygen

Carbon

Nitrogen

Correct answer:

Nitrogen

Explanation:

Amino acids, which make up proteins, have an amino group, which contains nitrogen. Carbohydrates and lipids contain the elements carbon, hydrogen, and oxygen, but they do not contain nitrogen.

Example Question #153 : Dna, Rna, And Proteins

Which of the following is not one of the four basic components of an amino acid?

Possible Answers:

Side chain

Basic amino group

Nitrogenous base

Acidic carboxyl group

Hydrogen atom

Correct answer:

Nitrogenous base

Explanation:

A nitrogenous base is a part of the DNA/RNA structure. They include adenine, guanine, cytosine, thymine, and/or uracil. All other answer choices are parts of amino acids.

Example Question #1 : Plant Biology

Which is of the following is not an adaptation/modification that enabled plants to move from aquatic to terrestrial environments as they evolved?

Possible Answers:

Thylakoid membranes

Cutin

Roots and root hairs

Stomata

Correct answer:

Thylakoid membranes

Explanation:

Thylakoid membranes are found within chloroplasts, which are used for photosynthesis. Plants found in both aquatic and terrestrial environments photosynthesize, so these membranes cannot be considered adaptations uniquely benefiting terrestrial plants.

Comparatively, cutin is a waxy coating found on various parts of plants that helps prevent water loss when exposed to air. Stomata are tiny openings in the epidermis of plants that allow for the exchange of carbon dioxide and oxygen while minimizing water loss. Roots and root hairs allow plants to absorb nutrients and water from the soil. Water loss was the primary challenge plants faced when moving from aquatic to terrestrial environments; cutin, stomata, roots, and root hairs all help terrestrial plants absorb and conserve water.

Example Question #1 : Plant Evolution

Which structures did not evolve after plants emerged onto land?

Possible Answers:

Stomata

Seeds

Waxy cuticles

Vascular transport

Cell walls

Correct answer:

Cell walls

Explanation:

Cell walls were present in plant cells before the transition to land. Seeds, stomata, waxy cuticles, and vascular transport all evolved to reduce water loss and circulate water to all areas of the plant. Water loss and circulation were not an issue before the transition to land; plants were forced to adapt these traits in order to survive in a terrestrial environment.

Example Question #2 : Plant Biology

As plants moved from water to land, they developed structures and lifestyles better suited to life in their new environment. Which of the following is not an example of these adaptations?

Possible Answers:

Decrease in rigidity 

Vascular tissue

Roots

Increase in vertical height

Cuticle

Correct answer:

Decrease in rigidity 

Explanation:

Plants developed more rigid structures to help maintain their growth on land as opposed to water.

Waxy cuticles developed to help reduce water loss/desiccation. Roots allowed plants greater access to water, as well as provided anchoring to the ground; this allowed plants to grow taller. Vascular tissue facilitated transport of water and nutrients to all parts of the plant. Stomata helped with gas exchange.

Example Question #33 : Divisions Of Life And Viruses

What is a distinct feature of a C4 plant?

Possible Answers:

Carbon fixation

Light independent reactions

Closed stomata during the day

Bundle-sheath cells

Correct answer:

Bundle-sheath cells

Explanation:

Carbon fixation converts inorganic carbon dioxide into organic carbon compounds, such as glucose and cellulose. This is a characteristic function of both C3 and C4, and is a primary purpose of light independent reactions.

Closed stomata during the day is a characteristic of CAM plants, which allows for the conservation of water that is usually lost during photorespiration.

Bundle-sheath cells are a characteristic of C4 plants. The presence of bundle-sheath cells isolates rubisco, preventing rubisco from binding to oxygen during photorespiration.

Example Question #3 : Plant Biology

Which of the following refers to the principle of alternation of generations in plants?

Possible Answers:

A life cycle which includes a unicellular haploid stage

Gamete-producing sporophytes

The differences between a tree and a seed

The need for external pollinators

A life cycle that includes a multicellular haploid stage

Correct answer:

A life cycle that includes a multicellular haploid stage

Explanation:

Plants have a multicellular haploid stage called the gametophyte. Gametophytes () produce gametes () through mitosis, which combine to produce a zygote (). The zygote grows into a multicellular, diploid sporophyte (), which produces spores () through meiosis. Those spores give rise to multicellular gametophytes.

Example Question #5 : Plant Biology

How is it believed that plants first became photosynthetic?

Possible Answers:

The chloroplast was a cluster of synthesized proteins, which evolved over time

A vacuole became specialized for photosynthesis

An ancestor of modern plants internalized a photosynthetic prokaryote through phagocytosis

The origin of the chloroplast is still largely unknown

Correct answer:

An ancestor of modern plants internalized a photosynthetic prokaryote through phagocytosis

Explanation:

The chloroplast is believed to have evolved from photosynthetic bacteria that formed a mutualistic symbiotic relationship with an ancestor of plants through endosymbiosis. There is lots of evidence supporting the endosymbiotic theory, which is based on the principle of one organism phagocytosing another, resulting in mutualism.

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