case 1 Flashcards
Explain the nucleus.
The nucleus contains DNA. The region of the neuron containing the nucleus is known as the cell body, soma, or perikaryon (Figure 8.2). The cell body is the metabolic center of the neuron. Nucleus consist of nuclear envelope, nucleolus and chromatin.
Explain the Golgi apparatus.
Golgi apparatus: modifies the product(proteins)(made in the endoplasmic reticulum of the Er. it has a place where it receives or ships/transports this. cis space→ receiving side. trans transported side. Organelle active in synthesis, modification, sorting and secretion of cell products.
Explain the relationship among organelles of the endomembrane system (figure 7,15)
Explanation
1- The nuclear envelope is connected to the rough ER which is continues with the smooth ER.
2- Membranes and proteins produced by the ER move via transport vesicles to the golgi.
3- The golgi pinches of transport vesicles and other vesticles that give rise to lysosomes other type of specialised vesicles and vacuoles.
4- The lysosome is available for fusion with another viscle for digestion
5- A transport vesticle carries proteins to the plasma membrane for secretion.
6- The plasma membrane expands of vesicles; proteins are secreted from the cel by exocytosis.
What are the differences and similarities between prokaryote and eukaryote?
- Similarities, consist of
- Plasma membrane
- Semifluid substance called cytosol
- Chromosomes
- Ribosomes.
Differences,
- Prokaryotes
o No nucleus
o DNA in an unbound region called the nucleoid
o No membrane-bound organelles
o Cytoplasm bound by the plasma membrane - Eukaryotic
o DNA in a nucleus that is bounds by a membranous nuclear envelope
o Membrane-bound organelles
o Cytoplasm in the region between the plasma membrane and nucleus
o Are generally larger than prokaryotic cells.
Explain the plasma membrane.
The plasma membrane is a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service to volume of every cell. (generally structure of a biological membrane is a double layer of phospholipids.)
Explain the cell size
- metabolic requirements set upper limits on the size of cells. The more energy the cell needs to produce the bigger the size is.
- The surface area to volume ratio of a cell is critical (As a cell increases in size, its volume grows proportionately
more than its surface area)
explain nuclear pores and nuclear limina.
Nuclear pores
* Pores regulate the entry and exit of molecules from the nucleus
* The nuclear size of the envelop is lined by the nuclear lamina,
which is composed of proteins and maintains the shape of the
nucleus
Explain ribosomes.
Ribosomes are complexes made of ribosomal RNA and protein. Ribosomes carry out protein synthesis in two locations
- In cytosol (free ribosomes)
- On the outside of the endoplasmic reticulum or nuclear envelope (bound ribosomes)
What is the endomembrane system and what does it exist of?
The endomembrane system exist if
- Plasma membrane
- Nuclear envelope
- Endo plasmatic reticulum
- Golgi system
- Lysosomes
- Vacuoles
(these components are either continuous or connected via transfer vesicle’s)
What is the ER?
The endoplasmic reticulum accounts for more than half of the total membrane in many eukaryotic cells. It is continuous with the nuclear envelope. There are two distinct regions the rough and smooth er.
Explain smooth ER
Smooth ER
- Synthesizes lipids
- Metabolizes carbohydrates
- Detoxifies drugs and poisons stores calcium lost.
Explain rough ER
Rough ER
- Has bound ribosomes, which
secrete glycoproteins (proteins
covalently bonded to
carbohydrates)
- Distributes transport vesicles,
secretory proteins surrounded
by membranes
- Is a membrane factory for the
cel
Explain lysosomes
Lysosomes
o lysosome is a membranous sac of hydrolytic enzymes that can
digest macromolecules
o Lysosomal enzymes work best in the acidic environment inside
the lysosome
o Hydrolytic enzymes and lysosomal membranes are made by
rough ER and then transferred to the Golgi apparatus for further
processing.
o Some types of cells can engulf another cell by phagocytosis; this
forms a food vacuole
o lysosome fuses with the food vacuole and digests the
molecules
o Lysosomes also use enzymes to recycle the cells own organelles
and macromolecules, a process called autophagy
Explain vacuoles.
- Vacuoles.
o Vacuoles are large vesicles derived from the ER and
Golgi apparatus
o Vacuoles perform a variety of functions in different
kinds of cells
o Food vacuoles are formed by phagocytosis
o Contractile vacuoles, found in many freshwater
protists, pump excess water out of cells
o Central vacuoles, found in many mature plant cells,
hold organic compounds and water
- What is an mitochondrion?
- Mitochondria are the sites of cellular respiration, a metabolic
process that uses oxygen to generate ATP
o Mitochondria are in nearly all eukaryotic cells
o They have a smooth outer membrane and an inner membrane folded into cristae
o The inner membrane creates two compartments;
- Intermembrane space
- Mitochondrial matrix.
o Some metabolic steps of cellular respiration are catalysed in the mitochondrial matrix.
o Cristae present a large surface area for enzymes that synthesize ATP.
