IB Bio SL quiz, Cells and Liver

Outline the three parts of the cell theory

• All cells come from pre-existing cells

• Cells are the smallest unit/building blocks of life

• All organisms are composed of one or more cells

Give examples that are exceptions to the cell theory

• Striated muscle cells, multiple nuclei, long fibers

• Giant algae, can grow up to 100mm, unicellular, size would usually require multiple small cells

• Aseptate fungal hyphae, sometimes not divided into individual cells

• Viruses

Outline uses of stem cells

• Unspecialized stem cells can divide

• Stem cells come from embryos, bone marrow, umbilical cord blood, adult tissue

• Stem cells can regenerate, repair diseased, damaged tissues in people

List the functions of life

• Nutrition

• Metabolism

• Growth

• Response

• Excretion

• Homeostasis

• Reproduction

What are the characteristics of eukaryotic cells?

• Large

• Complex

• Unicellular or multicellular

• Has a nucleus

• Has membrane bound organelles

• 80s ribosomes

• Cell membrane

• Cytoplasm

• Ribosomes

• DNA

What are the characteristics of prokaryotic cells?

• Small

• Simple

• Unicellular

• Has a nucleoid, no nucleus

• Circular DNA (plasmids)

• No membrane-bound organelles

• Pilli

• 70s ribosomes

Outline the evidence of endosymbiotic theory

• Mitochondria and chloroplasts show features common with prokaryotes

• Have their own DNA

• Surrounded by a double membrane

What cell organelle/component arose first during cell formation?

Cell membrane

Describe Louis Pasteur’s experiment

Had two flasks filled with nutrient broth, both had a cap with a long tube, one was boiled and didn’t have bacterial growth and the un-boiled one did, disproving the theory of spontaneous generation and proved that cells come from pre-existing cells

Compare and contrast the structure of sinusoids and capillaries

Compare: Both have walls 1 cell thick

Contrast: Sinusoids have holes

Outline how materials from red blood cells are recycled by the liver

• Erythrocytes have a lifespan of approximately 120 days

• Erythrocytes taken in by phagocytosis by Kupffer cells

• Hemoglobin splits into globin and heme groups

• Iron recycled

• Heme without iron becomes bilirubin

• Globin digested into amino acids

What’s the scientific name for red blood cells?

Erythrocytes

Outline the causes and consequences of jaundice

Causes:

• Hepatitis

• Liver cancer

• Cirrhosis

• Parasite infection

• Excess production of bilirubin

• Blocked ducts

• Gall stones

Consquences

• Yellowing of skin and whites of eyes

• Dark urine

• Grey feces

• Brain damage in infants

Explain the function of hepatocytes in protein metabolism

• Hepatocytes produce plasma proteins

• Plasma proteins are modified by Golgi apparatus

• Protein in then broken down into amino acids

Outline the circulation of blood to and from the liver

• Receives oxygenated blood by the hepatic artery, used to sustain liver cells

• Receives nutrient rich blood from the gut (gastrointestinal tract) via the portal vein

• Deoxygenated blood is transported from the liver via the hepatic vein

What is the scientific term for liver cells?

Hepatocytes

Outline the functions of the liver

• Stores and releases key nutrients such as glycogen, cholesterol and triglycerides

• Detoxifies potentially harmful ingested substances such as drugs, alcohol, bacteria

• Produces plasma proteins that function to maintain sustainable osmotic (water balance) conditions within the blood stream

• Breakdowns red blood cells and produces bile salts

What is the endosymbiotic theory?

• 2 billion years ago a bacterial cell was engulfed by a eukaryote

• Eukaryotes and prokaryotes have a symbiotic relationship

• Bacterial cell that was in the eukaryote eventually became a mitochondria/chloroplast

Outline the function of sinusoids

• Hepatocytes remove and add substances

• Site of exchanges between blood and hepatocytes

• Kupffer cells break down hemoglobin in red blood cells

• Wall is made up of hepatocytes