APII: Cell Structure Flashcards
(28 cards)
What are the two main structural components of the plasma membrane?
Phospholipids and proteins
The plasma membrane also contains carbohydrates and cholesterol.
What is the function of phospholipids in the cell membrane?
Form a double layered barrier impermeable to water
Polar phosphate parts are hydrophilic and on the outsides, while nonpolar lipid parts are hydrophobic and sandwiched in between.
What roles do proteins play in the cell membrane?
Structure, passage of H2O & solutes, receptor sites for hormones, antigens, and carrier molecules
Antigens act as identification markers that trigger immune responses.
What is cytoplasm?
Gel-like fluid inside the cell, a colloidal suspension
It is highly organized and contains organelles.
What are inclusions in the context of cell structure?
Temporary structures not part of the permanent machinery of cells
Examples include secretory vesicles, vacuoles, and lipid droplets.
What is the nucleus known for?
Control center of the cell
It directs all metabolic activity and contains genetic material.
What is DNA and what does it contain?
Deoxyribonucleic acid, containing chromosomes
Humans have 46 chromosomes, which are 23 homologous pairs from each parent.
What happens to DNA when it is uncoiled?
It is called chromatin
Individual chromosomes cannot be distinguished in this form.
What is the role of messenger RNA (mRNA) in the cell?
It tells other organelles what to do
mRNA is produced when part of DNA unzips.
How does the nuclear membrane differ from the cell membrane?
It is more permeable
This allows the passage of large proteins such as mRNA.
What is the nucleolus?
Area in the nucleus where RNA is produced
It stains darkly and is involved in the synthesis of ribosomal RNA.
What are mitochondria?
Mitochondria are the “power plants” of the cell that produce ATP (adenosine triphosphate).
They form bonds between ADP (adenosine diphosphate) and phosphate molecules.
What happens to ATP in the cell?
ATP leaves mitochondria and goes to other parts of the cell where it breaks back into ADP + P, releasing energy for use by other processes.
What are ribosomes?
Ribosomes are small granules of RNA in the cytoplasm that function in the synthesis of proteins for the cell.
What is the endoplasmic reticulum?
The endoplasmic reticulum is a complex series of membranous channels in the cytoplasm, consisting of rough and smooth types.
What is the rough endoplasmic reticulum?
The rough endoplasmic reticulum has ribosomes attached, appears rough, and synthesizes proteins to be shipped outside the cell.
What is the smooth endoplasmic reticulum?
The smooth endoplasmic reticulum has no ribosomes and functions in the production of certain lipids, such as steroids.
What is the Golgi apparatus?
The Golgi apparatus is the “packing and shipping plant” of the cell, consisting of a series of flattened membranous sacs.
It transports proteins and lipids from the E.R., which may be concentrated or modified.
What are lysosomes?
Lysosomes are membrane-enclosed sacs of digestive enzymes that destroy cellular debris and break down worn-out cell parts.
What role do lysosomes play in white blood cells?
White blood cells contain many lysosomes to destroy microorganisms and toxins through a process called phagocytosis.
What are the protein filament organelles within the cytoplasm?
Cytoskeleton and centrioles.
What are the protein filament organelles projecting outward?
Cilia and flagella.
