Life Processes Exam 3

What is not a step of the process of digestion?

salivation

In what part of the digestive tract does mechanical digestion begin?

mouth

What anatomical structure prevents a bolus of food from entering the trachea?

Epiglottis

What is the term used to describe wavelike contractions that move matter through the lumen of an organ or a vessel?

Peristalsis

Which of the stomach layers is responsible for allowing the stomach to stretch and mechanically break down food?

Oblique Layer

Which layer of the stomach is closest to the lumen?

Mucosa Layer

Which digestive enzyme breaks down proteins?

Pepsin

What is not one of the five steps of digestion?

hydrolysis

Which layer of the intestine contains the majority of the blood vessels and nerves found in the small intestine?

Submucosa

What organ is predominantly responsible for neutralizing acidic chime in the duodenum?

Pancreas

What anatomical structure is primarily responsible for increasing the absorptive surface area of the small intestine?

Villi

The longest part of the large intestine is

Colon

The primary function of the large intestine is

to reabsorb water

A major difference between DNA and RNA is

That DNA is double stranded while RNA is single stranded

Which of the following enzymes is responsible for building the complementary strand of DNA during DNA replication?

Polymerase

What term best describes a non-coding portion of DNA that is not part of any gene?

Intron

When mRNA is being processed in the nucleus what structure made of RNA and protein is responsible for joining the exons together?

Spliceosome

When a ribosome is building a protein where do tRNAs first enter the large ribosomal subunit?

A site

Where does transcription take place in human cells?

Nucleus

Which term most accurately describes the human use of a biological system to achieve a desired purpose?

Biotechnology

Which of the following is best defined as the process of artificially making many copies of a particular section of DNA?

PCR

What best describes the process of cloning?

The production of identical copies of DNA, cells, or organisms through an asexual means

What is the key factor that makes recombinant DNA (rDNA) different from regular DNA?

Recombinant DNA contains genes from more than one source organism

What tool is commonly used for genome editing?

CRISPR

Gene editing is best defined as

Targeting specific DNA sequences for replacement or removal

Current human health applications for genetic engineering include everything but

altering a patient’s DNA so that they can regrow a severed limb

Genetic engineering has been used to create plants with what enhancements?

Fruits with increased shelf life

Grains with increased nutritional value

Crops that are toxic to insects

Genetic engineering in animals has produced what kind of enhancements?

Fish that grow twice as fast

Sterile mosquitos

Cattle that produce human growth hormone in their milk

Which enzyme does CRISPR use?

Cas9

In reference to genetic engineering what term is best used to describe a means by which genes of interest can be inserted into a cell?

Vector

Xenotransplantation refers to?

transplanting non-human organs into humans

What genomic subspecialities focusses on how genes of different organisms differ from each other and how the differences evolved?

Comparative Genomics

Gene Therapy is best defined as?

The insertion of genetic material into human cells for the treatment of a disorder

Which genomic subspeciality focuses on understanding cellular proteins?

Proteomics

What is ex vivo gene therapy?

The genetic alteration of patient stem cells occurs in the lab

About how much of the human genome codes for functional proteins?

2%

Which subspecialty of genomics focusses on identifying coding and non-coding areas of the human genome and determining how the two work together?

Functional genomics

What is an example of biotechnology that was discussed in lecture?

Genetically engineering bacteria to metabolize crude oil

what type of reaction is used in the digestive system to break down macromolecules into their monomer subunits?

1. mechanical digestion

2. chemical digestion: hydrolysis of food macromolecules into monomer subunits

What are the five general steps of the digestive process?

Ingestion

Digestion

Movement

Absorption

Elimination

Ingestion

taking in food via the mouth

Digestion

breaking down food into smaller pieces

Movement 

food passed from one organ to the next to process the food

absorbing nutrients

eliminate any indigestible material

Absorption

monomers from chemical digestion cross the wall of the GI tract

they then enter GI cells

then passed back into blood stream

Elimination

molecules that cant be digested are removed from the body

Path food takes in human digestive system

Mouth

pharynx

esophagus

stomach

duodenum 

jejunum

Mouth

receives food begins mechanical and chemical digestion

where saliva is produced

Saliva

begins chemical digestion

contains amylase and lipase

Pharynx

connects mouth and nasal cavity to the throat

Esophagus

connects the pharynx to the stomach

Epiglottis

connects the pharynx to the stomach

acts like a gate preventing food from entering the trachea

Peristalsis

wavelike contractions of muscles along the lumen that move matter in a specific direction

Sphincter

circular muscles that line various body tubes

when they contract the tubes close and when they relax the tube opens

helps keep stomach acid from splashing back up into the unprotected esophagus

Stomach

primary site of chemical digestion

absorbs alcohol

Stomach Layers

Muscularis

• Circular Layer

• Longitudinal layer

• oblique layer

Mucosa Layer

Oblique Layer

made of smooth muscle

allows the stomach to stretch

aids in mechanical digestion

Mucosa Layer

layer closest to the lumen

made of multiple gastric pits containing gastric glands

Gastric Glands

produce gastric juices that contain pepsin, hydrochloric acid, and mucus

chyme

partially digested food

pyloric sphincter

only allows a small amount of acidic chyme to pass into the small intestine at a time

What digestive enzymes does the stomach secrete

pepsin, hydrochloric acid, mucus

The stomach is not affected by the digestive juices because?

the mucosa layer

thick layer that acts as a barrier

Five parts of the small intestine

Lumen'

Mucosa

Submucosa

Muscularis

Serosa

Lumen

open area of an organ

Mucosa

innermost layer of an organ

closest to the lumen

secretes digestive enzymes and mucus

mucus protects the tissue from the digestive enzymes

Submucosa

second layer of the organ

made of loose connective tissue

contains blood, lymphatic vessels, and nerves

Muscularis

third layer

has two layers of smooth muscle

acts under nervous and hormonal control

creates peristalsis

Serosa

outermost layer

secretes lubricating fluid to protect organs from when they brush up against each other

lines the abdominal cavity

Diverticulosis

associated with the mucosa

portion of mucosa pushes through other layers of the intestine and form pouches where food gets stuck

when the pouches are inflamed or infected that’s diverticulitis

Are there any disorders associated with each tissue layer of the small intestine?

There are no known maladies associated with each layer of the small intestine

Inflammatory Bowel Disease (IBD)

blood vessels of the bowel are inflamed leading to chronic diarrhea, abdominal pain, fever, and weight loss

Irritable Bowel Syndrome (IBS)

associated with the muscularis

have pain in abdominal wall when muscularis contracts and causes constipation or diarrhea

Small Intestine parts

Duodenum

Jejunum

Illeum

Duodenum is aided by

Pancreas and gallbladder

pancreas

secretes bicarbonate to neutralize stomach acid and digestive enzymes (trypsin)

Bicarbonate release is controlled by what?

controlled by secretin which is released when there is a pH drop in the duodenum

Gallbladder

Stores bile

bile release is cck

which is released when fats enter the duodenum

Bile

emulsifier made by the liver that breaks down fats into smaller droplets

Jejunum

continues to secrete digestive enzymes and starts process of absorption

Illeum

absorbs nutrients like b12, bile salts, carbs, proteins, and fats

Mucosa of small intestine is modified for absorption how?

adding villi and microvilli to increase surface area to volume ratio

Digestive Enzymes produced by small intestine

Lipase: breaks down lipids

Amylase: breaks down carbohydrates

Protease: breaks down proteins

Large Intestine is made up of what?

Cecum

Colon

Rectum

What is the purpose of the appendix?

may play a role in the immune system or helps maintain healthy gut microbiome but true purpose is unknown

Heartburn/ GERD

occurs when cardiac sphincter don’t close properly and stomach acid back flows into the esophagus

Accessory Organs of the digestive tract

Salivary Glands

Liver

Gallbladder

Pancreas

DNA vs RNA

DNA:

• found in nucleus and mitochondria

• stores genetic info

• deoxyribose sugar

• A,T, C, G

• double stranded

• transcribed to create RNA

RNA:

• found all throughout the cell

• assists in processing genetic info

• ribose sugar

• A, U, C, G

• single stranded

• involved in gene regulation

• is translated to produce proteins

DNA Replication

process of copying DNA helix

OG strand of DNA is used as a template strand for formation of new complementary DNA strand

enzymes and steps involved in DNA replication

DNA helicase

DNA polymerase

leading and lagging strand

DNA Ligase

two new double helix molecules that are completely identical are created

DNA helicase

unwinds the double stranded DNA strand

breaks down the weak H bonds between base pairs

DNA polymerase

positions and joins the new complementary DNA nucleotides to DNA strand

Leading Strand

strand of DNA that is synthesized continuously and follows helicase

Lagging Strand

DNA strand moving in the opposite direction of DNA helicase and has to wait for DNA to unwind creating Okazaki Fragments

Okazaki Fragments

short broken fragments of DNA

DNA ligase

binds the Okazaki fragments back together to reform the coiled structure

What needs to happen for a mutation to occur during DNA replication?

An repair enzyme has to be unable to fix the mutation

Mutation

permanent change in sequence of nucleotide bases

Four types of RNA

mRNA
tRNA

rRNA

small RNA

Messenger RNA (mRNA)

carries genetic info from DNA in the nucleus to the ribosome in the cytoplasm

Ribosomal RNA (rRNA)

joins with proteins to form the small and large ribosome subunits that then join together and act as a workbench to manufacture proteins