12.4: Review Questions - Biology

12.4: Review Questions - Biology

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1. Why are the washing steps necessary in the ELISA test?

2. Why are positive and negative controls always required for immunological tests? (be specific)

3. What is the purpose of the enzyme conjugated to the secondary antibody in the ELISA test?

4. Why is it important to include a negative control well on the Biolog plate?

5. What does it mean if an environmental sample does not match 100% to a species in the database?

6. What possible error do you think could occur by inoculating too much bacteria into the Biolog wells?

ALMA Peers Back 12.4 Billion Years and Discovers the Most Ancient Galaxy of Its Kind Ever Observed

ALMA detected emissions from carbon ions in the galaxy. Spiral arms are visible on both sides of the compact, bright area in the center of the galaxy. Credit: ALMA (ESO/NAOJ/NRAO), T. Tsukui & S. Iguchi

Analyzing data obtained with the Atacama Large Millimeter/submillimeter Array (ALMA), researchers found a galaxy with a spiral morphology only 1.4 billion years after the Big Bang. This is the most ancient galaxy of its kind ever observed. The discovery of a galaxy with a spiral structure at such an early stage is an important clue to solving the classic questions of astronomy: “How and when did spiral galaxies form?”

“I was excited because I had never seen such clear evidence of a rotating disk, spiral structure, and centralized mass structure in a distant galaxy in any previous literature,” says Takafumi Tsukui, a graduate student at SOKENDAI and the lead author of the research paper published in the journal Science. “The quality of the ALMA data was so good that I was able to see so much detail that I thought it was a nearby galaxy.”

The Milky Way Galaxy, where we live, is a spiral galaxy. Spiral galaxies are fundamental objects in the Universe, accounting for as much as 70% of the total number of galaxies. However, other studies have shown that the proportion of spiral galaxies declines rapidly as we look back through the history of the Universe. So, when were the spiral galaxies formed?

Tsukui and his supervisor Satoru Iguchi, a professor at SOKENDAI and the National Astronomical Observatory of Japan, noticed a galaxy called BRI 1335-0417 in the ALMA Science Archive. The galaxy existed 12.4 billion years ago [1] and contained a large amount of dust, which obscures the starlight. This makes it difficult to study this galaxy in detail with visible light. On the other hand, ALMA can detect radio emissions from carbon ions in the galaxy, which enables us to investigate what is going on in the galaxy.

The researchers found a spiral structure extending about 15,000 light-years from the center of the galaxy. This is one third of the size of the Milky Way Galaxy. The estimated total mass of the stars and interstellar matter in BRI 1335-0417 is roughly equal to that of the Milky Way.

“As BRI 1335-0417 is a very distant object, we might not be able to see the true edge of the galaxy in this observation,” comments Tsukui. “For a galaxy that existed in the early Universe, BRI 1335-0417 was a giant.”

Then the question becomes, how was this distinct spiral structure formed in only 1.4 billion years after the Big Bang? The researchers considered multiple possible causes and suggested that it could be due to an interaction with a small galaxy. BRI 1335-0417 is actively forming stars and the researchers found that the gas in the outer part of the galaxy is gravitationally unstable, which is conducive to star formation. This situation is likely to occur when a large amount of gas is supplied from outside, possibly due to collisions with smaller galaxies.

The fate of BRI 1335-0417 is also shrouded in mystery. Galaxies that contain large amounts of dust and actively produce stars in the ancient Universe are thought to be the ancestors of the giant elliptical galaxies in the present Universe. In that case, BRI 1335-0417 changes its shape from a disk galaxy to an elliptical one in the future. Or, contrary to the conventional view, the galaxy may remain a spiral galaxy for a long time. BRI 1335-0417 will play an important role in the study of galaxy shape evolution over the long history of the Universe.

“Our Solar System is located in one of the spiral arms of the Milky Way,” explains Iguchi. “Tracing the roots of spiral structure will provide us with clues to the environment in which the Solar System was born. I hope that this research will further advance our understanding of the formation history of galaxies.”

Synthetic biology approaches to dissecting linear motor protein function: towards the design and synthesis of artificial autonomous protein walkers

Molecular motors and machines are essential for all cellular processes that together enable life. Built from proteins with a wide range of properties, functionalities and performance characteristics, biological motors perform complex tasks and can transduce chemical energy into mechanical work more efficiently than human-made combustion engines. Sophisticated studies of biological protein motors have provided many structural and biophysical insights and enabled the development of models for motor function. However, from the study of highly evolved, biological motors, it remains difficult to discern detailed mechanisms, for example, about the relative role of different force generation mechanisms, or how information is communicated across a protein to achieve the necessary coordination. A promising, complementary approach to answering these questions is to build synthetic protein motors from the bottom up. Indeed, much effort has been invested in functional protein design, but so far, the "holy grail" of designing and building a functional synthetic protein motor has not been realized. Here, we review the progress made to date, and we put forward a roadmap for achieving the aim of constructing the first artificial, autonomously running protein motor. Specifically, we propose to break down the task into (i) enzymatic control of track binding, (ii) the engineering of asymmetry and (iii) the engineering of allosteric control for internal communication. We also propose specific approaches for solving each of these challenges.

Keywords: Allostery Energy transduction Motor protein Processivity Synthetic biology Thermal fluctuations.

Conflict of interest statement

The authors declare that they have no conflicts of interest.


The structures of linear protein…

The structures of linear protein motors drawn to scale and oriented so that…

Pathway to generating synthetic motor…

Pathway to generating synthetic motor proteins. a Modular assembly of protein motors using…

Designing allosteric communication to create…

Designing allosteric communication to create an autonomous walker protein. a Allostery by putting…

Regulation of circRNA biogenesis

Unlike linear RNAs terminated with 5' caps and 3' tails, circular RNAs are characterized by covalently closed loop structures with neither 5' to 3' polarity nor polyadenylated tail. This intrinsic characteristic has led to the general under-estimation of the existence of circular RNAs in previous polyadenylated transcriptome analyses. With the advent of specific biochemical and computational approaches, a large number of circular RNAs from back-spliced exons (circRNAs) have been identified in various cell lines and across different species. Recent studies have uncovered that back-splicing requires canonical spliceosomal machinery and can be facilitated by both complementary sequences and specific protein factors. In this review, we highlight our current understanding of the regulation of circRNA biogenesis, including both the competition between splicing and back-splicing and the previously under-appreciated alternative circularization.

Keywords: alternative circularization back-splicing circular RNA circularization complementary sequence splicing.


Back-splicing for circRNAs. Pre-mRNA can…

Back-splicing for circRNAs. Pre-mRNA can go through either high efficient canonical splicing to…

Two possible models for circRNA…

Two possible models for circRNA formation. ( A ) The “exon skipping” or…

The competition of RNA pairing…

The competition of RNA pairing for splicing or back-splicing. ( A ) (…

Possible mechanisms for alternative circularization.…

Possible mechanisms for alternative circularization. ( A ) Multiple circRNAs can be processed…

12.4: Review Questions - Biology

Here&rsquos master post of some great MCAT study materials and resources. Click on the bold titles to open links to folders containing the files listed below. Good luck.

2015 KAPLAN MCAT REVIEW BOOKS (pdf links listed below)

  • Molecular Biology Cellular Respiration
  • Genes
  • Microbiology
  • The Eukaryotic Cell The Nervous System
  • The Endocrine System
  • The Digestive and Excretory Systems
  • The Cardiovascular System The Respiratory System
  • Muscle, Bone and Skin
  • Populations
  • The Berkeley MCAT Review - Biology Part 1 (2011)
  • The Berkeley MCAT Review - Biology Part 2 (2011)
  • Atoms, Molecules and Quantum Mechanics
  • Gases, Kinetics, and Chemical Equilibrium
  • Thermodynamics
  • Solutions
  • Heat Capacity/Phase Change/Colligative Properties
  • Acids & Bases
  • Electrochemistry
  • Intro to Chemistry
  • Electrostatics
  • Gases
  • Thermodynamics and Thermochemistry
  • The Berkeley MCAT Review - General Chemistry Part 1 (2011)
  • Molecular Structure
  • Hydrocarbons, Alcohols, Substitutions
  • Carbonyls and Amines
  • MCAT Physics Book (2015)
  • Translation Motion
  • Force
  • Equilibrium, Torque and Energy
  • Momentum, Machines, and Radioactive Decay
  • Fluids and Solids
  • Waves
  • Electricity and Magnetism
  • Light & Optics
  • Linear Momentum


These materials will help build your knowledge and test taking skills, they may not fit the current MCAT exam criteria but it will definitely build your knowledge of the subjects being tested.

12.4: Review Questions - Biology

SABER Annual Meeting 2021

Held virtually the last four Fridays in July

Conference Schedule

Session 1: Friday, July 9, 2021

Session 2: Friday, July 16, 2021

Session 3: Friday, July 23, 2021

Session 4: Friday, July 30, 2021

Annual SABER business meeting: August 6, 2021

Each session will be approximately four hours beginning at 10am Pacific/1pm Eastern to 2pm Pacific/5pm Eastern. More details will be coming as the schedule is finalized.

Registration Fees

Registration fees for the 2021 Annual Meeting

  • $50 Tenure/ tenure-track faculty
  • $25 All others
  • Limited fee waivers available (first-come, first-served)

Additional Workshops

DBER Scholars-in-Training Career Panel

Open to Students and Post-Docs

  • Thursday, July 22, 2021
  • 9 am - 12 pm PT (12 - 3 pm ET)
  • Free of charge. S ign up with conference registration (forthcoming)
  • View panel information.
  • Share about your career interests to help shape this event to meet your needs!

Assess What's Important:

Creating assessments that show how students use their knowledge and how instruction promotes that knowledge.

  • Thursday, July 29, 2021
  • 10 am - 1 pm PT (1 - 4 pm ET)
  • Free of charge. Registration details forthcoming.
  • Presenters: Diane Ebert-May, Jennifer Doherty, Amanda Sorensen, and Luanna Prevost.
  • View workshop abstract, presenter bios, learning outcomes, and workshop timeline/activities.

Workshop registration is integrated into registration for the main meeting.

Bill Wood Graduate Student Talk Award

All graduate students who submitte d a short talk abstract will be considered f or the Bill Wood Graduate Student Talk Award.

As this award was not given in 2020, multiple awards will be given in 2021. This year all current graduate students and individuals who were graduate students in July 2020 who give a short talk at SABER will be considered for the award.

All graduate students who submit an abstract for a short talk as first author are automatically considered for the Bill Wood Award. The Abstract Committee reviews all abstracts submitted and selects those to be presented as short talks at the SABER meeting using the published evaluation criteria. The Bill Wood Award Committee then attends each graduate student first-authored short talk at the meeting and selects the winners. Winners will be presented a monetary award sponsored by Pearson. Thank you Pearson!

See the rubric for talk evaluations HERE.

Keynote Speakers

Opening keynote: July 9

Closing the Metacognitive Equity Gap: Research Shows Us How

Dr. Saundra McGuire, Professor (Emerita) of Chemistry and Director (Emerita) of the Center for Academic Success, Louisiana State University, and author of the best-selling books Teach Students How to Learn and Teach Yourself How to Learn

Dr. McGuire will share research-based learning strategies that have proven effective for increasing STEM student success. She will also discuss research on promoting student learning through metacognitive approaches, with a particular lens on improving equity in the classroom. Her work blends cognitive science and learning theory, and these evidence-based approaches will be broadly applicable to all STEM instructors.

Closing keynote: July 30

Dr. Niral Shah, Assistant Professor of Learning Sciences and Human Development, University of Washington

Dr. Shah will discuss his research on race and racism in STEM education, and how instructors can incorporate anti-racist practices in the classroom to improve student outcomes. His work investigates what shapes student identities and participation in the classroom, particularly in mathematics and computer science education.

Abstract Information

The SABER 2021 Annual Meeting will include long talks, short talks, roundtables, posters, and workshops, as in prior years.

Call for abstracts issued: February 19, 2021

Abstract submission deadline: March 22, 2021

Decisions and feedback posted: May 19, 2021

CourseSource Online Writing Studios

In partnership with the SABER meeting, CourseSource is hosting Online Writing Studios twice this summer: Session 1 July 19-21 from 12-4 pm Eastern each day for participants writing about online and/or in-person lessons and Session 2 August 16-18 from 12-4 pm Eastern each day for participants writing about online lessons only.

Check out their website for information on eligibility and benefits. Apply online and contact Erin Vinson with questions. Application review will begin on May 24, 2021.

12.4: Review Questions - Biology

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited.

Feature Papers represent the most advanced research with significant potential for high impact in the field. Feature Papers are submitted upon individual invitation or recommendation by the scientific editors and undergo peer review prior to publication.

The Feature Paper can be either an original research article, a substantial novel research study that often involves several techniques or approaches, or a comprehensive review paper with concise and precise updates on the latest progress in the field that systematically reviews the most exciting advances in scientific literature. This type of paper provides an outlook on future directions of research or possible applications.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to authors, or important in this field. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Departmental Roster — includes total scores and subscores (if applicable) of all students tested, listed alphabetically by last name.

Departmental Summary: Total Scores and Subscores — includes the frequency distributions of total scores and subscores, showing the percent of students scoring below each percentile. The departmental mean scale score and standard deviation are also shown. A Departmental Summary does not include scores of students who answered fewer than 50% of the test questions in one or both sections of a test.

Departmental Summary: Assessment Indicators — provides a list of the mean (average) percent correct of test questions answered in particular subdomains/content areas for the group as a whole.

Departmental Demographic Summary Report — provides student demographic information taken directly from the answer sheets and summarized for the group as a whole.

Individual Student Report — includes total score and subscores for each student tested, along with interpretive information.

For more information about other reports, see the Reports section.


Chapter 3: Cell Division

Principles of Cell Division
The Cell Cycle
A Cell Clock
Activity 3.3.1: Frequency of Cell Division
Comparing Mitosis and Meiosis
Activity 3.7.1: Comparing Meiosis and Mitosis
Reproduction and Cell Division
Abnormal Meiosis: Nondisjunction

Chapter 4: Genes and Heredity

Early Beliefs and Mendel
Single-Trait Inheritance
Selective Breeding
Multiple Alleles
Incomplete Dominance
Case Study: A Murder Mystery
4.6 Dihybrid Crosses
Activity 4.6.1: Genetics of Corn

Chapter 4 Summary
Chapter 4 Review

Chapter 5: The Source of Heredity

Early Developments in Genetics
Development of the Chromosomal Theory
Morgan's Experiments and Sex-Linkage
Activity 5.3.1: Sex-Linkage in Fruit Flies
Case Study: Tracing the Haemophilia Gene
Looking Inside the Chromosome
Discovering the Structure of DNA
The Structure of DNA
Genes That Change Position
Gene Research and Technologies
DNA Fingerprinting
Gene Therapy

Careers in Science
Chapter 5 Summary
Chapter 5 Review

Unit 2 Performance Task: Investigating Human Traits
Unit 2 Review

Regulation of mouse NK cell development and function by cytokines

Natural Killer (NK) cells are innate lymphocytes with an important role in the early defense against intracellular pathogens and against tumors. Like other immune cells, almost every aspects of their biology are regulated by cytokines. Interleukin (IL)-15 is pivotal for their development, homeostasis, and activation. Moreover, numerous other activating or inhibitory cytokines such as IL-2, IL-4, IL-7, IL-10, IL-12, IL-18, IL-21, Transforming growth factor-β (TGFβ) and type I interferons regulate their activation and their effector functions at different stages of the immune response. In this review we summarize the current understanding on the effect of these different cytokines on NK cell development, homeostasis, and functions during steady-state or upon infection by different pathogens. We try to delineate the cellular sources of these cytokines, the intracellular pathways they trigger and the transcription factors they regulate. We describe the known synergies or antagonisms between different cytokines and highlight outstanding questions in this field of investigation. Finally, we discuss how a better knowledge of cytokine action on NK cells could help improve strategies to manipulate NK cells in different clinical situations.

Keywords: TGF-beta cytotoxicity interferons interleukin-12 interleukin-15 interleukin-18 natural killer cells signal transduction.

Watch the video: Ears Review Questions. City College Shahdara ; 10th Bio Ch (May 2022).