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AP Biology Unit 8L: Biomes, Primary Productivity & Ecosystem Energetics — practice questions — page 2

Explore 57 free Unit 8L: Biomes, Primary Productivity & Ecosystem Energetics questions in AP Biology Biology. Open each question or exercise to read its content, reference answers and available explanation.

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Unit 8L: Biomes, Primary Productivity & Ecosystem Energetics questions and exercises with answers

Showing questions 31–57 of 57.

C4 plants lack photorespiration becauseRead the answer and worked solution →Blackman's Law of Limiting Factors states thatRead the answer and worked solution →In the Z-scheme, electrons removed from PS II are replenished byRead the answer and worked solution →The stages of the Calvin cycle in order areRead the answer and worked solution →After microsporogenesis, the cells of the resulting microspore tetrad have a ploidy of:Read the answer and worked solution →The germ pores in a pollen grain are regions where:Read the answer and worked solution →In a mature 2-celled pollen grain at the time of shedding, the two cells present are:Read the answer and worked solution →Approximately what percentage of angiosperms shed pollen at the 2-celled stage?Read the answer and worked solution →In a typical angiosperm ovule, the small opening in the integuments through which the pollen tube usually enters is the:Read the answer and worked solution →A mature angiosperm embryo sac is typically:Read the answer and worked solution →Transfer of pollen grains from the anther to the stigma of the **same flower** is called:Read the answer and worked solution →Which of the following is the **only** type of pollination that brings genetically different pollen grains to the stigma?Read the answer and worked solution →Wind-pollinated flowers typically have all of the following features EXCEPT:Read the answer and worked solution →Production of unisexual flowers on different plants (each plant either male or female) is called:Read the answer and worked solution →In a plant breeding programme, removal of anthers from a flower bud before dehiscence is called:Read the answer and worked solution →The ploidy of the primary endosperm nucleus (PEN) in angiosperms is:Read the answer and worked solution →After double fertilisation, the zygote develops into the embryo while the:Read the answer and worked solution →Coconut water (the liquid inside a tender coconut) is best described as:Read the answer and worked solution →Triple fusion takes place in:Read the answer and worked solution →In a dicot embryo, the portion of the embryonal axis above the level of cotyledons is the:Read the answer and worked solution →In a monocot (grass) embryo, the cotyledon is called the:Read the answer and worked solution →The simplest amino acid, whose R group is a hydrogen atom, is:Read the answer and worked solution →Proteins are polymers made up of:Read the answer and worked solution →The chemical bond that links amino acids together in a protein is the:Read the answer and worked solution →Enzymes are best described as:Read the answer and worked solution →Nucleic acids such as DNA and RNA are polymers of:Read the answer and worked solution →Different amino acids differ from one another in their:Read the answer and worked solution →

Worked practice questions

C4 plants lack photorespiration because

  1. Photorespiration is light-dependent only
  2. C4 plants have no light reactions at all
  3. Bundle sheath cells concentrate CO2 around RuBisCO
  4. RuBisCO is absent in C4 plants altogether
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Correct answer: C. Bundle sheath cells concentrate CO2 around RuBisCO

C4 plants use PEP carboxylase in mesophyll to grab CO2 and shuttle it as malate/aspartate to bundle sheath cells, where it is released as concentrated CO2 around RuBisCO. High CO2:O2 ratio suppresses oxygenase activity.

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Blackman's Law of Limiting Factors states that

  1. The factor in least supply limits the rate
  2. All factors equally limit the process
  3. Only light limits photosynthesis ever
  4. Only CO2 limits photosynthesis ever
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Correct answer: A. The factor in least supply limits the rate

**Blackman (1905):** in a multi-factor process, the rate is set by the factor nearest its minimum value. In photosynthesis, light may saturate at 10%, then CO2 or temperature takes over as the limiting factor.

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In the Z-scheme, electrons removed from PS II are replenished by

  1. Splitting of water at the OEC site
  2. Cyclic transfer back from PS I always
  3. NADPH oxidation at the stroma side
  4. ATP hydrolysis at the membrane
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Correct answer: A. Splitting of water at the OEC site

Oxygen-evolving complex (OEC, water-splitting) on the lumen side of PS II strips electrons from H2O, giving 4H+ + O2 per 2 water. These electrons replace the ones boosted out of P680 by photon absorption.

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More Biology topics

Unit 5C: Non-Mendelian Genetics & Population TransmissionUnit 2B: Membrane Transport, Tonicity & Cell SizeUnit 8K: Human Organ Systems & HomeostasisUnit 3B: Photosynthesis, Respiration & Cellular EnergyUnit 7B: Population Genetics & Hardy-Weinberg EvolutionUnit 2G: Osmoregulation & Membrane DynamicsUnit 8R: Environmental Pollution & Organismal HealthUnit 5D: Organismal Reproduction & Life Cycles