Academic Decathlon_Science 1 Questions

 Which type of cell in the nervous system is the MAIN cell used to communicate across long distances? 

•  choroid plexus cells 

• neurotransmitters

• ependymal cells

• neurons

Answer explanation

 The nervous system consists of two main cell types, neurons, and glia. Neurons are used to communicate across long distances. 

 Which of the following measurements varies MOST across a human’s lifetime? 

•  the amount of neural connections 

• the neuron proliferation rate 

• the number of neurons 

• the neuron death rate 

Answer explanation

 Unlike most other cells, neurons are not easily created. Most of a human’s neurons exist by the time of birth. However, neural connections vary over time. 

 DNA encodes instructions for building 

•  lipids 

   

• proteins 

• nucleic acids 

• carbohydrates 

Answer explanation

 DNA, which is stored in cell nuclei, encodes instructions for building proteins. First, DNA is transcribed into RNA, then RNA is translated into proteins. 

Tags

NGSS.HS-LS1-1

 Which cellular feature is LEAST particular to neurons? 

•  synapse 

• dendrite

• myelin

• neuronal membrane

Answer explanation

 The neuronal membrane is analogous to a cell membrane in other eukaryotic cells. Dendrites, synapses, myelin, and Nodes of Ranvier are unique to neurons. 

 “Dendrite” originates from the Greek word meaning 

•  “tenth” 

• “toothlike”

• “thick” 

• “treelike” 

Answer explanation

 The term “dendrite” originates from the Geek word for “treelike” due to the branching nature of dendrites. 

 Myelin functions as a(n) 

•  resistor 

• transistor 

• insulator

• conductor 

Answer explanation

 Myelin is a fatty compound that surrounds and insulates the axon. This increases the speed of the electric signals traveling through the axon. 

 Where does a neuron release its signal? 

•  the Nodes of Ranvier 

   

• the axon terminals

• the soma 

• the dendrites 

Answer explanation

 Neurons release signals, in the form of neurotransmitters, at the axon terminals. 

 Where does a neuron USUALLY receive a signal? 

•  the dendritic spines 

• the axon terminals 

• the axon hillock 

• d. the myelin 

Answer explanation

 Neurons usually receive signals at one of their dendritic spines. The receiving neuron is called a postsynaptic neuron. 

 A synapse is defined as the 

•  packet of neurotransmitters 

• neuron sending a signal 

• point at which two neurons communicate 

• d. neuron sending a signal 

• e. space between neurons 

Answer explanation

 A synapse is the point at which two neurons communicate. Because the neurons are not physically connected, the signal must pass through the synaptic cleft. 

 Where in neurons are neurotransmitters produced? 

•  vesicles 

• dendrites 

• synapse 

• soma 

• axon 

Answer explanation

 Neurotransmitters are produced in the soma and occupy packets called vesicles.