Answer:
<u><em>Unlike a flat mirror, the curved surface of the spoon's bowl bounces incoming rays back towards a central focus point lying between your face and the centre of the spoon's. In passing through this point, rays from the upper part of your face are reflected downward, while those from the lower part are reflected upward.</em></u>
hey please mark me as the brainliest if this helped you out<3
Levels<span> of </span>organization<span> in ecology include the population, community, ecosystem, and biosphere. An ecosystem is all the living things in an area interacting with all of the antibiotic parts of the </span>environment<span>.</span>
Answer:
The question lacks the illustrative diagram, the diagram has been attached as an image.
The correct answer, according to the picture is A.
Explanation:
All cells undergo division (mitosis or meiosis). Meiosis reduces the chromosomal number of the daughter cells by half. According to the question, The female species of Myrmecia pilosula ant has diploid cells total number of 2 chromosomes.
At the metaphase stage of meiosis I, homologous chromosomes (similar but non-identical chromosomes received from each parent) aligns at the center/equator of the cell called METAPHASE PLATE. This alignment is done when spindle fibres attach to the kinetochores of the chromosomes.
Option A in the diagram depicts this arrangement of homologous chromosomes in the centre of the cell. Note that, each chromosome has replicated to form SISTER chromatids held together at the centromere. These chromosomes will be pulled apart in the next stage (Anaphase).
Option B depicts only one replicated chromosome
Option D depicts separation of sister chromatids (only one chromosome)
Option E depicts separation of sister chromatids of two chromosomes which occurs in the Anaphase of meiosis II
I’m pretty sure it’s winter because most mammals like to hibernate so I think the population is gonna increase lost rapidly in winter or march
Answer:
1. nerve stimulus
4. calcium channels open
10. acetylcholine vesicles move to endplate
7. exocytosis occurs releasing acetylcholine into synaptic cleft
3. acetylcholine binds to receptor
6. impulse rides along sarcolemma
9. impulse enters the cells via the t-tubule
5. sarcoplasmic reticulum releases calcium
8. calcium binds to troponin moving tropomyosin out of the way
2. myosin attaches to actin causing a twitch
Explanation:
The central nervous system generates an action potential (<u>1</u>) that travels to the muscle fiber activating the calcium channels (<u>4</u>). Calcium triggers vesicles fusion to the presynaptic membrane (<u>10)</u> releasing acetylcholine (Ach) into the synaptic space (<u>7</u>). Once there, Ach binds to its receptors (<u>3</u>) on the postsynaptic membrane of the skeletal muscle fiber, causing ion channels to open. Positively charged sodium ions cross the membrane to get into the muscle fiber (sarcoplasm) and potassium leaves the cell. The difference in charges caused by these ions transport charges positively the muscle fiber membrane (<u>6</u>). It depolarizes. The action potential enters the t-tubules (<u>9</u>) depolarizing the inner portion of the muscle fiber.
Contraction initiates when the action potential depolarizes the inner portion of the muscle fiber. Calcium channels activate in the T tubules membrane, releasing calcium into the sarcolemma (<u>5</u>). At this point, the muscle is at rest, and the tropomyosin is inhibiting the attraction strengths between myosin and actin filaments. <em>Tropomyosin is obstructing binding sites for myosin on the thin filament</em>. When calcium binds to troponin C, troponin T alters the tropomyosin position by moving it and unblocking the binding sites (<u>8)</u>. Myosin heads join to the uncovered actin-binding points forming cross-bridges <u>(2</u>), and while doing so, ATP turns into ADP and inorganic phosphate, which is released. Myofilaments slide impulsed by chemical energy collected in myosin heads, producing a power stroke. The power stroke initiates when the myosin cross-bridge binds to actin (<u>2</u>). As they slide, ADP molecules are released. A new ATP links to myosin heads and breaks the bindings to the actin filament. Then ATP splits into ADP and phosphate, and the energy produced is accumulated in the myosin heads, which starts a new binding cycle to actin. Finally, Z-bands are pulled toward each other, shortening the sarcomere and the I-band, producing muscle fiber contraction.
