I have no questions xp

During the cross-bridge cycle in muscle cells, myosin motors hydrolyze ATP as fuel to create a pulling force on actin fibers. Pl

exis [7]

Answer and Explanation:

In rest, attraction strengths between myosin and actin filaments are inhibited by the tropomyosin. When the muscle fiber membrane depolarizes, the action potential caused by this depolarization enters the t-tubules depolarizing the inner portion of the muscle fiber. This activates calcium channels in the T tubules membrane and releases calcium into the sarcolemma. At this point, tropomyosin is obstructing binding sites for myosin on the thin filament. When calcium binds to the troponin C, the troponin T alters the tropomyosin by moving it and then unblocks the binding sites. Myosin heads bind to the uncovered actin-binding sites forming cross-bridges, and while doing it ATP is transformed 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. 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. Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.

7 0

3 years ago

Transverse waves contain _____ & _____, while longitudinal waves contains ______ & _________.

nlexa [21]

Transverse waves contain crests & troughs

while longitudinal waves contains compressions &rarefactions.

4 0

3 years ago

What do all vertebrates and invertebrates have in common?

Rudiy27

Animals can be classified into two main groups:vertebrates and invertebrates. The main difference between vertebrates and invertebrates is thatinvertebrates, like insects and flatworms, do nothave a backbone or a spinal column. Examples ofvertebrates include humans, birds, and snakes. hope this helped

8 0

3 years ago

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Norway rats have 42 chromosomes in their diploid cells. If a diploid rat cell enters meiosis, how many chromosomes and double-he

vitfil [10]

Answer:

21 chromosomes

Explanation:

Meiosis is a type of cell division that produces 4 haploid daughter cells (i.e., gametes) from a single diploid cell. This parental cell undergo one (1) cycle of DNA replication and two (2) cell divisions, thereby, in the case of the Norway rats that have 42 chromosomes, the final number will be 21 (21 x 2= 42)

7 0

3 years ago

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Having freckles (F) is dominant over not having freckles (f). A parent with freckles is crossed with a parent without freckles.

Step2247 [10]

Answer:

This is a trick question, and only because the question is vague

Explanation:

Use a Punnet Square to figure out the percentages.

If the parent with freckles (let's just call them Parent A) is homozygous dominant, their genotype would be FF. The parent without freckles (Parent B) has a genotype of ff.

In any situation, the probability of these two having a child that is homozygous dominant for freckles is 0%. (see punnet squares for more info).

Now here's where it gets a little more confusing because the question is kind of vague on this.

Assuming that Parent A is homozygous dominant (both genes for this are dominant (FF)), then the probability of having a heterozygous (non-identical genotype letters, meaning they carry the recessive trait) genotype is 100%. However, if Parent A is also heterozygous, then that percentage decreases to 50%

For Situation A (Parent A is homozygous dominant), the probability of a homozygous recessive genotype is 0%

For Situation B (Parent A is heterozygous dominant), the probability of a homozygous recessive child is 50%.

Please see the Punnet square I made for more information.

Key:

- Homozygous Dominant: FF

- Heterozygous Dominant: Ff

- Homozygous Recessive: ff

(heterozygous recessive does not exist, because that would mean one of the genes is dominant, which would overpower the recessive gene)

I really hope this helps, and if you're confused by this, please do not hesitate to let me know!

8 0

3 years ago

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