BIO Test #8

The survival of some bacteria even in harsh and extreme environmental conditions is facilitated by which structure?

A. 

Gram-positive membrane

B. 

Gram-negative membrane

C. 

Endospore 

D. 

Glycocalyx

E. 

Endotoxin

C. 

Endospore 

A. Gram postive has a thick peptidoglycan cell wall (purple). This serves in strucural support

B. Gram negative has a thin petidoglycan cell wall, but it has endotoxins (LPS) (pink)

C. Endospores are structures that sourround the genetic cmaterial in bad conditions, allowing its survival in dangerous environments

Which of the following is a function of the lymphatic system?

A. 

Transport fats towards the digestive system

B. 

Return fluids that have escaped from blood vessels 

C. 

Transport of nutrients towards target cells

D. 

Synthesis of erythrocytes 

E. 

Take up particles except larger proteins

B. 

Return fluids that have escaped from blood vessels 

A. Lymphatic system transports fats away from the small intestine. Fats absorbed in the small intestine go to the lymphatic system then are put back in the blood.

B. The lymphatic system collects excess interstitial fluid (escaped from blood capillaries) and returns it to the cardiovascular system, maintaining fluid balance).

C. This is done by the cirvulatory system, not lymphatic

D. Red blood cells are produced in the red bone marrow. (Hematopoeitc stem cells)

E. Lymphatic system actually can take big proteins from the blood that cannot pass through capillaries.

Which of the following prevents acetylcholine from remaining for too long in the synapse?

A. 

Choline acetyltransferase

B. 

Passive diffusion into pre-synaptic cell

C. 

Acetylcholinesterase 

D. 

Degradation by post-synaptic cell surface receptors

E. 

Uptake by post-synaptic cell

C. 

Acetylcholinesterase 

Degradation of the acetylcholine signal in the synaptic cleft may occur in various mechanisms

• Hydrolysis by acetylcholinesterase

• Diffusion away from the synaptic cleft

• Active reuptake by the pre-synaptic cell

Acetlycholine never enters the post snyaptic cell, it just binds to receptors on the post synaptic cell, which causes na+ influx which causes a depolarization event.

Full acetylcholine pathway

• Ca2+ released in pre synaptic membrane

• This causes acetlycholine to be released in the synaptic celft (NMJ)

• Acetylcholine diffuses (passive) across the cleft and binds to post synaptic receptors

  • Acetylcholine in the cleft can by hydrolyized by acetylcholinesterase

• Post synaptic receptors cause Na+ influx, which depolarizes the cell and starts an AP

What is the earliest stage seen during embryonic development?

A. 

Morula

B. 

Zygote 

C. 

Blastocyst

D. 

Blastomere

E. 

Trophoblast

B. 

Zygote 

Stages of embryonic development:

• Zygote

• Blastomeres

• Morula

• Blastocyst

• Implantation

• Gastrulation

Zombies

Bring

More

Babies

Into

Graves

All of the following are characteristics of epigenetics EXCEPT one. Which one is the EXCEPTION?

A. 

Modifies nucleotide sequence

B. 

Heritable

C. 

Contributes to phenotypic variability

D. 

Influences gene expression

E. 

May result from external or environmental factors

A. 

Modifies nucleotide sequence

Epigenetics involves heritable phenotypes that result from changes to the expression of the genome without modifying the nucleotide sequence. Epigenetics regulates when certain genes are expressed. In other words, it allows specific genes to turn “on” or “off”. Since epigenetics do not alter the nucleotide sequence, epigenetic changes explain why genetically identical organisms can still have noticeable physical differences.

DNA Methylation

• Decreases gene expression

• Winds DNA tighter around histone proteins

DNA Acetylation

• Increases gene expression

• Causes DNA to unwing around histones

Which of the following develops into macrophages?

A. 

Neutrophils

B. 

Mast cells

C. 

Eosinophils

D. 

Monocytes

E. 

Dendritic cells

D. 

Monocytes

Which of these is involved in the polyspermy blocks?

A.

Hyperpolarization

B.

Intracellular acetylcholine release

C.

Extracellular calcium influx

D.

Release of cortical granules

E.

Synthesis of ZP3

D.

Release of cortical granules

Fast Block

• Na+ rushes into the egg, causing depolarization

• This alters the charge of the membrane, not letting any other sperm fuse with the membrane

Slow Block

• Cortical granules releasees ca2+ into the intermebrane space.

• This expands the space (zona pollucida expands outwards) and inactivates zp3 receptors, which the sperm normally attach to.

To reliably insert a DNA segment into a plasmid vector, a restriction enzyme must first be used on a palindromic sequence called a recognition site. Which of the following sequences would be ideal for this purpose?

A. 

B. 

C. 

D. 

E. 

C.

Which of the following is the product of spermatogenesis?

A. 

Primary spermatocytes

B. 

Spermatogonia

C. 

Secondary spermatocytes

D. 

Spermatids

E. 

Spermatozoa

E. 

Spermatozoa

G. oys Spermatagonium

P Primary Spermatocyte
S. Secondary Spermatocyte
S. Spermatid
S Spermatazoa

Which of the following scientists proposed the theory of trait inheritance through use and disuse?

A. 

Lamarck

B. 

Darwin

C. 

Cuvier

D. 

Mendel

E. 

Wallace

A. 

Lamarck

Lamarck

• Use and disuse

Cuvier

• Catastrophism

The process of photosynthesis can be summarized as follows:

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Which process is ultimately responsible for the production of oxygen?

A. 

Breakdown of glucose

B. 

Splitting of H₂O

C. 

Splitting of CO₂

D. 

Breakdown of mesophylls

E. 

Aerobic respiration

B. 

Splitting of H₂O

• Glucose (C6H12O6) is synthesized from carbon dioxide (CO2) during the Calvin Cycle (light-independent reactions) using the energy provided by ATP and NADPH.

• Oxygen (O2) is produced from the splitting of water (H2O) during the light-dependent reactions, as shown in the image where water is split at Photosystem II (PS II) releasing oxygen, protons (H+), and electrons.

Honeybees and ants secrete a trail of a chemical factor after locating a source of food, allowing them to communicate the location of the food to others. This form of communication is accomplished using which type of compound?

A. 

Pheromone 

B. 

Hormone

C. 

Neurotransmitter

D. 

Primary messenger

E. 

Secondary messenger

A. 

Pheromone 

Releaser pheremones

• Short lived, reversible pheromes

• Food trails

Primer pheremones

• Caues physiological changes