Chapter 3.3 - Cell organelles Flashcards
What is the primary function of the nucleus?
Storage and transmission of genetic information to the next generation of cells
-also used to synthesize the proteins necessary for cell function
Surrounding the nuclus is a barrier called the ______ composed of ______
Surrounding the nuclus is a barrier called the nuclear envelope composed of two membranes
At regular intervals along the surface of the nuclear envelope the two membranes are joined to each other, forming the rims of circular openings known as ______
At regular intervals along the surface of the nuclear envelope the two membranes are joined to each other, forming the rims of circular openings known as nuclear pores
Nuclear pores allow the movement of ______ and _____ between the nucleus and cytoplasm
Nuclear pores allow the movement of RNA and Proteins that modulate gene expression between the nucleus and cytoplasm
WIthin the nucleus, DNA, in association with proteins, forms a fine network of threads: ______
WIthin the nucleus, DNA, in association with proteins, forms a fine network of threads: chromatin
During cell division, the chromatin threads become tightly condensed, forming rodlike bodies known as ______
During cell division, the chromatin threads become tightly condensed, forming rodlike bodies known as chromosomes
Inside the nucleus is a densely staining filamentous region without a membrane called the
Nucleolus
What is the purpose of the nucleolus?
(lecture)
Synthesis of ribosomal RNA
What is the function of nuclear pores?
(lecture)
Allows selective movement of molecules in and out of the nucleus
-communication with cytosol
Lecture definition of chromatin?
Consists of DNA associated with proteins
-condenses to form chromosomes during cell division
Lecture definition of Nuclear envelope?
Double layered porous membrane
-separates nucleus from cytoplasm
Most cells have one nucleus
Except (2)
- Red blood cells: have no nucleus (maximize space for hemoglobin)
- Skeletal muscle tissue: multinucleate
- Made of many precursor cells fused together to form one large cell with many nuclei
Ribosomes are responsible for:
Protein synthesis
“protein facotries of a cell”
Ribosomes are composed of:
Two subunits: Large and small
Each subunit of the ribosome is composed of _____ and ________
Each subunit of the ribosome is composed of proteins and ribosomal RNA
The subunits of ribosomes join prior to ______, forming _____ ribosomes
The subunits of ribosomes join prior to protein synthesis, forming functional ribosomes
What are the two major types of functional ribosomes?
Free ribosomes- in cytoplasm
Bound ribosomes - on Endoplasmic Reticulum
What is the endoplasmic reticulum?
Fluid filled membranous system distributed throughout the cytoplasm
What are the functions of the Rough endoplasmic Reticulum?
- Synthesis of proteins with bound functional ribosomes
- Post-translational modification of proteins
- includes cleavage and glycosylation
- needed to make membranes
- needed for secretory proteins
What are the functions of the smooth endoplasmic reticulum?
- Synthesize lipids (fatty acids, steroids)
- Stores Ca2+ (in muscle cells = sarcoplasmic reticulum)
- Drug detoxification (liver cells)
The _____ is a series of closely apposed, flattened membranous sacs that are slightly curved, forming a cup-shaped structure
The Golgi Apparatus is a series of closely apposed, flattened membranous sacs that are slightly curved, forming a cup-shaped structure
What are cisternae?
Sets of flattened slightly curved membrane bound sacs stacked in layers (make up the golgi)
What are the functions of the Golgi Apparatus?
- Post-translational modification of proteins made in the RER
- Sorts and packages proteins
What are three options for proteins following packaging in the golgi?
- Secreted via exocytosis
- Become integral membrane proteins
- become proteins of lysosomes, ER, or Golgi
What are lysosomes?
Small, spherical organelles containing digestive enzymes
What is the function of lysosomes?
Breakdown extracellular and intracellular debris
-Destroy endocytosed bacteria, viruses
What pH do lysosomes function at, how is the pH maintained?
pH of 5, maintained by protein pumps
How are lysosomes made?
Enzyme made in ER -> Golgi packages them into vesicles -> enzyme filled vesicle = lysosome
What are peroxisomes?
Small organelles containing oxidative enzymes
What is the function of Peroxisomes?
Use oxygen to remove hydrogen from molecules
-Breakdown longchain fatty acids, alcohol, drugs (abundant in liver & kidney)
What is a toxic product from peroxisomes? How do peroxisomes combat this?
H2O2
Peroxisomes contain the antioxidant enzyme, catalase that breaks H2O2 into water and oxygen
What two organelles have 2 membranes?
Mitochondria and Nucleus
The inner membrane of the mitochondria folds to form:
Cristae
What are four cell types that have an abundance of Mitochondria?
Skeletal muscle
Heart muscle
Liver
Sperm
Mitochondria has its own DNA. What type of DNA is this?
Double stranded circular DNA
What are three general functions of the cytoskeleton?
- Maintain cell shape
- Maintain Organelle position
- Mediate cell and organelle motility
What are the three cytoskeletal filaments?
- Microfilament (actin filament)
- Intermediate filament
- Microtubule
What is the protein subunit of microfilaments?
Function (3)?
G-actin
- -Support cell,
- determine cell shape
- cell movement
What is the protein subunit of intermediate filaments? What are three functions
There are several, including Keratin
- intermediate filaments are part of desmosomes (via keratin)
- Support cell,
- Provide mechanical strength
- desmosomes
What is the protein subunit of microtubules?
What are 2 functions?
Tubulin = large hollow tubes
- support for cell
- movement of organelles (tracks)
