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monitta
3 years ago
8

What evidence places fish as the first vertebrates​

Biology
1 answer:
Whitepunk [10]3 years ago
7 0

Answer:

Fossils

Explanation:

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12. A plant has a dominant phenotype but an unknown genotype. The proper experiment to determine its correct genotype would be a
jekas [21]

Answer:

the correct answers are as follows

12:

b. Testcross- an organism with dominant phenotype but unknown genotype is crossed with homozygous recessive organism for the same trait. Based on the results obtained, if all offsprings have the same phenotype, then the parent is homozygous, but when a 1:1 ratio is observed in the offsprings, then the parent is heterozygous.

13.

e. Watson and Crick- they both used the crystallographic images from Franklin, analyzed them to first elucidate the 3D structure of the DNA and propose it to the world.

14.

c. Intracellular and commonly found in the cytoplasm- the receptors of steroid hormones are generally present within the target cell either in the cytoplasm or nucleus, since they alter gene expression.

15

e. Certain prokaryotes/bacteria- this is a process that will enable disease-causing pathogens to communicate and cooperate with their group, by the release of autoinducers that increase their cell density.

5 0
2 years ago
When does the total number of chromosomes get reduced from 46 pairs to 23 individual chromosomes? View Available Hint(s) When do
ivann1987 [24]

Answer:

23 pairs of chromosomes (46 individual chromosomes) are redued to 23 individual chromosomes in meiosis I.

During Meiosis I

Explanation:

Meiosis is a type of cell division that results in four daughter cells with each having half the number of chromosomes as in the parent cell. During meiosis, cell division occurs twice because before the two halves of a duplicated chromosome (sister chromatids) is separated, it still needs to separate homologous pair of chromosomes, which is a similar but non-identical pair of chromosomes received from both parent. Hence, meiosis occurs in a two step division process; Meiosis I and Meiosis II.

Note that, a diploid cell contains 23 pairs of chromosomes ( 46 chromosomes in total). Each pair of chromosome is from the haploid gamete produced by each parent after meiosis.

Before going into meiosis I, the cell must first undergo growth and replicate its DNA in the interphase stage just like in mitosis. In the Prophase I of meiosis I, chromosomes condense as in mitosis but also pair up. Each chromosome aligns with its homologue pair to form a structure called TETRAD or BIVALENT.

Homologous pairs, not individual chromosomes (23 pairs in number) line up at the metaphase plate for separation during metaphase I.

In anaphase I, the homologues are pulled apart by the spindle fibres and move apart to opposite ends of the cell. The sister chromatids of each chromosome, however, remain attached to one another and don't come apart. Hence, the cell now has 23 chromosomes on one side of the cell, and another 23 on the other side.

After cytokinesis (division of the cytoplasm) in meiosis I, two daughter cells are produced and each now possesses 23 individual chromosomes (haploid) different from the parental 23 pairs (diploid).

N.B: Sister chromatids separate in the anaphase of meiosis II, where each chromatid is counted as an individual chromosome.

4 0
3 years ago
I have mutant cells that make no pfk2enzyme. i measure rates of oxygen consumption in these mutant cells and compare them to wil
Kazeer [188]

The correct answer is that mutant cells will exhibit diminished oxygen consumption; decreased glycolysis results in decreased Kreb's cycle and electron transport chain.

The PFK2 enzyme catalyzes the generation of F26BP, this binds with the allosteric site of PFK-1 and increases the affinity of PFK-1 with F6P and also decreases the affinity of allosteric inhibitors citrate and ATP to PFK-1. Thus, PFK-1 will combine with F6P at a greater rate.

This ultimately results in more glycolysis, thus, more ETC and more consumption of O2. If there is no PFK2, then there will be a reduction in glycolysis, TCA, ETC, and consumption of oxygen.

The PFK2 is an enzyme accountable for monitoring the rates of gluconeogenesis and glycolysis in the human body. In the absence of glycolysis, there will be a reduction in TCA, ETC, and consumption of O2.

5 0
3 years ago
how does the energy of the reactants and products differ between an energy absorbing reaction and an energy releasing reaction
Nikitich [7]
In an energy absorbing reaction, the energy of the products is greater than the energy of the reactants. In an energy releasing reaction, the energy of the reactants is greater than the energy of the products.
6 0
3 years ago
In what way are the humerus and the femur similar?
dimaraw [331]
The humerus-
A long bone of the upper forelimb. It articulates proximally with the scapula to form the soulder joint and distally with the radius and ulna to form the elbow joint.
<span>Proximally the humerus has a rounded projection known as the head. </span>

Cranially at the lateral aspect of the head is a large prominence- the greater tubercle. The lesser tubercle lies medially. Both tubercles act as a sight for muscle attachment. At the distal end of the humerus is a condyle which articulates with the radius & ulna & forms part of the elbow.

The diaphysis of the humerus is twisted.
<span>In the dog a supra condylar foramen is present- a large hole in the condyle.
</span>
The Femur-This is the thigh bone and is the largest bone in the body, it is a long bone and is similar in structure to the humerus in that it has a head, neck, shaft & lateral & medial condyles. The femoral head articulates with the acetabulum proximally to form the hip joint, lateral to the head is the greater trochanter and on the medialTh side is a lesser trochanter (for muscle attachment). At the distal end of the femur are 2 condyles that articulate with the tibia to form the stifle joint. Between the 2 condyles is the trochlear groove along which the patella can move.

Here is some information. Hope this helps ☺
3 0
3 years ago
Read 2 more answers
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