
Concept explainers
Following gastrulation, the cells that have folded inward develop into
- a. endoderm.
- b. mesoderm.
- c. ectoderm.
- d. All of the above are correct.

Introduction:
Gastrulation is a period in the development of an embryo of animals, in which a single layered blastula folds itself in such a way that it forms a cup shaped structure called gastrula. Gastrula further contains two or three layers of tissue. It includes the endoderm, ectoderm and mesoderm.
Answer to Problem 1MCQ
Correct answer:
The cells that have folded inward develop into endoderm, after gone through the gastrulation phase. Therefore, option (a) is correct.
Explanation of Solution
Reason for the correct statement:
The blastula rearranges itself to develop the gastrula, following gastrulation the cells that fold inward develop into the endoderm. Endoderm is the inner most layer which contributes to the development of an embryo
Option (a) is given as “endoderm”.
As, “endoderm is the inner most layer which is formed by the folding of cells after gastrulation phase. Endoderm is the primary germ layer which contributes to the development of an embryo in early stage”, it is the right answer.
Hence, option (a) is correct.
Reasons for the incorrect statements:
Option (b), is given as “mesoderm”.
Mesoderm is the middle layer formed between ectoderm and endoderm. This is the third primary germ layer which also contributes to the development of an embryo. Mesoderm is formed by the interaction of two germ layers including ectoderm and endoderm. Hence, it is a wrong answer.
Option (c), is given as “ectoderm”.
Ectoderm is the outermost germ layer that also forms during the development of an embryo. It covers the outside of the embryo. Hence, it is a wrong answer.
Option (d), is given as “all of the above are correct”.
Endoderm, ectoderm and mesoderm all are the primary germ layers which are formed during the development of an embryo. Ectoderm is the outer layer of tissue and mesoderm is the inner layer of tissue. The cells that have folded inward result in the formation of endoderm. Hence, it is a wrong answer.
Hence, options (b), (c), and (d) are incorrect.
Endoderm is formed by the inward folding of cells followed after gastrulation. Endoderm is the primary germ layer which contributes to the development of an embryo in the early stage.
Want to see more full solutions like this?
Chapter 21 Solutions
Biology: Concepts and Investigations
Additional Science Textbook Solutions
Biological Science (6th Edition)
Applications and Investigations in Earth Science (9th Edition)
Genetics: From Genes to Genomes
Campbell Essential Biology (7th Edition)
HUMAN ANATOMY
Biology: Life on Earth with Physiology (11th Edition)
- With reference to their absorption spectra of the oxy haemoglobin intact line) and deoxyhemoglobin (broken line) shown in Figure 2 below, how would you best explain the reason why there are differences in the major peaks of the spectra? Figure 2. SPECTRA OF OXYGENATED AND DEOXYGENATED HAEMOGLOBIN OBTAINED WITH THE RECORDING SPECTROPHOTOMETER 1.4 Abs < 0.8 06 0.4 400 420 440 460 480 500 520 540 560 580 600 nm 1. The difference in the spectra is due to a pH change in the deoxy-haemoglobin due to uptake of CO2- 2. There is more oxygen-carrying plasma in the oxy-haemoglobin sample. 3. The change in Mr due to oxygen binding causes the oxy haemoglobin to have a higher absorbance peak. 4. Oxy-haemoglobin is contaminated by carbaminohemoglobin, and therefore has a higher absorbance peak 5. Oxy-haemoglobin absorbs more light of blue wavelengths and less of red wavelengths than deoxy-haemoglobinarrow_forwardWhich ONE of the following is FALSE regarding haemoglobin? It has two alpha subunits and two beta subunits. The subunits are joined by disulphide bonds. Each subunit covalently binds a haem group. Conformational change in one subunit can be transmitted to another. There are many variant ("mutant") forms of haemoglobin that are not harmful.arrow_forwardWhich ONE of the following is FALSE regarding haemoglobin? It has two alpha subunits and two beta subunits. The subunits are joined by disulphide bonds. Each subunit covalently binds a haem group. Conformational change in one subunit can be transmitted to another. There are many variant ("mutant") forms of haemoglobin that are not harmful.arrow_forward
- During a routine medical check up of a healthy man it was found that his haematocrit value was highly unusual – value of 60%. What one of the options below is the most likely reason? He will have a diet high in iron. He is likely to be suffering from anaemia. He lives at high altitude. He has recently recovered from an accident where he lost a lot of blood. He has a very large body size.arrow_forwardExplain what age of culture is most likely to produce an endospore?arrow_forwardExplain why hot temperatures greater than 45 degrees celsius would not initiate the sporulation process in endospores?arrow_forward
- Endospore stain: Consider tube 2 of the 7-day bacillus culture. After is was heated, it was incubated for 24 hours then refrigerated. Do you think the cloudiness in this tube is due mostly to vegetative cells or to endospores? Explain your reasoningarrow_forwardReactunts C6H12O6 (Glucose) + 2NAD+ + 2ADP 2 Pyruvic acid + 2NADH + 2ATP a. Which of the above are the reactants? b. Which of the above are the products? c. Which reactant is the electron donor? GHz 06 (glucose) d. Which reactant is the electron acceptor? NAD e. Which of the products have been reduced? NADH f. Which of the products have been oxidized? g. Which process was used to produce the ATP? h. Where was the energy initially in this chemical reaction and where is it now that it is finished? i. Where was the carbon initially in this chemical reaction and where is it now that it is finished? j. Where were the electrons initially in this chemical reaction and where is it now that it is finished? 3arrow_forwardThere is ________ the concept of global warming. Very strong evidence to support Some strong evidence to support Evidence both supporting and against Evidence againstarrow_forward
- How many types of reactions can an enzyme perform?arrow_forwardYour goal is to produce black seeds resistant to mold. So you make the same cross again (between a homozygous black seeded, mold susceptible parent and a homozygous white seeded and mold resistant parent), and, again, advance progeny by SSD to create 100 F10 generation plants. Based on the information you obtained from your first crossing experiment (Question #4), how many F10 plants would you expect to have black seeds and be resistant to mold? Assume that a toxin produced by the mold fungus has been isolated. Only mold resistant seeds will germinate in the presence of the toxin. Could you use this toxin screening procedure to have segregation distortion work in your favor in the F2 generation? Explain your answer. Info from Question 4 a. P Locus (Seed Color): Hypothesis: The null hypothesis (H₀) is that seed color is controlled by alleles at a single locus. Observed Data: Total white seeds: 45 (resistant plants) + 6 (susceptible plants) = 51 Total black seeds: 7 (resistant…arrow_forward10. Consider the following enzyme and its substrate where the "+" and "-" indicate cations and anions, respectively. Explain which of the following inhibitors could inhibit this enzyme? Which type of inhibitor would it be and why? (Video 5-2) Substrate Enzyme Potential inhibitorsarrow_forward
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage LearningHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning





