An organism that has the same genes as the organism it was produced from

Early settlers in the town of Dry Gulch drilled wells to pump as much water as they wanted from the single aquifer beneath the t

OleMash [197]

Answer: B. under use; it is a scarce resource.

Explanation:

Early settlers in the town of Dry Gulch drilled wells to pump as much water as they wanted from the single aquifer beneath the town. (An aquifer is an underground body of water.) As more people settled in Dry Gulch, the aquifer level fell and new wells had to be drilled deeper at higher cost.Residents of Dry Gulch have a private incentive to under use water because it is a scarce resource.

8 0

3 years ago

Hey guys. So I need your help I have this rock presentation assignment worth 90 points and I have to find a good title. It’s abo

Arturiano [62]

Answer:

stone is stone , the most beautiful stone it is right I think

6 0

3 years ago

Why is the aplysia such a popular animal for single-cell studies of learning?

Feliz [49]

Aplysia is a marine gastropod mollusc which is an often used model organism in neuroscience, especially on the cellular biology of learning and memory. What makes them easy to work with are their giant neurons, which are one of the largest. Aplysia neurons are suitable for studies of how neurons and neural circuits control behaviours. Its defensive reflex has been studied because it is mediated by electrical synapses, which allow several neurons to fire synchronously.

5 0

3 years ago

Check all that apply as characteristics of myelinated axons. Check All That Apply Myelinated axons transmit nerve impulses via c

stiv31 [10]

Answer:

Myelinated axons utilize fewer voltage-gated channels than unmyelinated axons of the same length and diameter.

Myelinated axons are more energy efficient than unmyelinated axons.

Explanation:

Neurons are cells that specialize in transmitting messages to each other using a type of electrical signal. These signals carry information from outside your body to the brain, while others are the instructions for the various organs, glands and muscles to carry out functions.

Neurons receive these signals from other neighboring neurons through their dendrites. The signal then travels to the soma of the neuron, which is the main body of the cell, and finally travels down the axon to the synapse (space between the end of a neuron and another cell). The axon is a neuronal extension through which the electrical signal travels, extending from the soma to other neurons.

There may be layers of myelin, which consist of a layer of fat, covering the axons and where they have the function of acting as insulators to help keep the electrical signal inside the cell, which makes it move faster increasing the speed of transmission of the nerve impulse.

1) Myelinated axons transmit nerve impulses via continuous conduction. FALSE. In the axon, nodes of Ranvier are found at regular intervals along the length of the axon in the myelin sheath that surrounds it. These are small spaces that expose the axon membrane to the extracellular fluid and serve to allow the nerve impulse to travel faster, in a jumping manner and with less chance of error.

2) Myelinated axons transmit nerve impulses in the same manner as unmyelinated axons. FALSE. In an unmyelinated axon, the movement of voltage across the membrane is due to ion flux that is limited by the time it takes for sodium ions to diffuse into the axon. Myelinated axons conduct faster because they are shorter than unmyelinated axons. In the latter, transmission is continuous but slower.

3) Myelinated axons utilize fewer voltage-gated channels than unmyelinated axons of the same length and diameter. TRUE. The action potential conduction jumps from node to node, thereby they need fewer voltage-gated channels. Unmyelinated axons need voltage-gated channels in along the entire axon.

4) Myelinated axons are more energy efficient than unmyelinated axons. TRUE. The rate at which sodium input through one node can depolarize the axon at the next node is related to the current and capacitance across the membrane. Myelinated axons have faster action potential conduction because it jumps from node to node, thereby they use less energy because they don't have to travel the entire length.

5) Myelinated axons would be unaffected by diseases that attack the CNS. FALSE. For example, Multiple sclerosis (MS) is a demyelinating disease of the CNS in which the immune system attacks the myelin sheath or the cells.

6 0

3 years ago

DESCRIBE the internal anatomy of skeletal muscle, using each of the following terms: ACTIN, MYOSIN, THIN FILAMENT, THICK FILAMEN

jasenka [17]

INTERNAL ANATOMY OF SKELETAL MUSCLE : SKELETAL MUSCLE IS OTHERWISE CALLED AS STRIATED OR VOLUNTARY MUSCLE. THEIR ACTIVITIES ARE UNDER THE VOLUNTARY CONTROL OF NERVOUS SYSTEM. THEREFORE, THEY ARE KNOWN AS VOLUNTARY MUSCLES. PRIMARY FUNCTION OF THIS MUSCLE IS LOCOMOTION AND CHANGES IN BODY POSTURE.

EACH MUSCLE IS MADE UP OF NUMBER OF MUSCLE BUNDLES OR FASCICLES. THESE FASCICLES ARE HELD TOGETHER BY A COMMON COLLAGENOUS CONNECTIVE TISSUE LAYER CALLED FASCIA.

EACH MUSCLE IS COMPOSED OF NUMEROUS MUSCLE FIBRES AND IT IS MULTINUCLEATED, CROSS STRIATED CYLINDRICAL CELLS. IT IS MADE UP OF SARCOLEMMA OR CELL MEMBRANE ENCLOSING SARCOPLASM (CYTOPLASM) . NUMBER OF EVENLY DISTRIBUTED LONGITUDINAL THREADS CALLED MYOFIBRILS ARE PRESENT IN THE SARCOPLASM.

MUSCLE-FASCICULE-FIBRE-MYOFIBRILS-MYOFILAMENTS

EACH MUSCLE IS AN INDIVIDUAL CELL AND CONSISTS OF FOLLOWING PARTS.

SARCOLEMMA, SARCOPLASM, NUCLEI, MYOFIBRILS, MYOFILAMENTS, MITOCHONDRIA, SARCOPLASMIC RETICULUM.

SARCOLEMMA IS CELL MEMBRANE OF MUSCLE FIBRES AND SARCOPLASM IS SEMIFLUID CYTOPLASM OF MUSCLE.

NUCLEI ARE MULTIPLE IN NUMBER AND OVAL IN SHAPE, PERIPHERAL IN DISTRIBUTION BENEATH THE SARCOLEMMA.

MYOFIBRILS ARE CONTRACTILE UNBRANCHED THREADS SITUATED ALONG THE MUSCLE FIBRE. IT CONSIST OF ALTERNATE A-BAND

AND I-BAND. EACH MYOFIBRILS CONSISTS OF LONGITUDINALLY ARRANGED PROTEIN FILAMENTS SUCH AS THIN FILAMENT CONSISTS OF ACTIN, TROPOMYOSIN, TROPONIN WHEREAS THICK FILAMENT CONSISTS OF MYOSIN . THESE ARE CALLED MYOFILAMENTS.

MITOCHONDRIA PROVIDES ENERGY FOR THE WORK OF MUSCLE FIBRE.

BESIDES THE ABOVE COMPONENTS THERE ARE THREE TYPES OF SUPPORTING TISSUES WHICH HELPS IN ORGANIZATION OF SKELETAL MUSCLES. THESE ARE.

ENDOMYSIUM : IT IS A DELICATE SHEATH OF CONNECTIVE TISSUE WHICH COVERS EACH MUSCLE FIBRE OUTSIDE THE SARCOLEMMA.

PERIMYSIUM : THE MUSCLE FIBRES ARE GROUPED INTO FASCICULI EACH FASCICULUS IS COVERED BY A CONNECTIVE TISSUE SHEATH CALLED PERIMYSIUM.

EPIMYSIUM : THE ENTIRE MUSCLE IS COVERED BY A SHEATH OF CONNECTIVE TISSUE KNOWN AS THE EPIMYSIUM.

5 0

3 years ago