mcdb 1a midterm 2

What structures do all cells have?

A cell membrane, ribosomes, genetic material, and cytoskeletal elements

what are the main components of a prokaryotic cell?

Fimbriae, nucleoids, ribosomes, plasma membrane, cell wall, and flagella

Define what a cytoskeletal element is

they are rod like or tubular proteins that provide structural support and help with movement across the cell

in essentiality, what is a nucleoid?

linear DNA

what are fimbriae?

they allow prokaryotic cells to attach to surfaces or other cells

What are flagella?

they are long, thin projections coming off of the surface of the cell. They help with propelling or moving the cell through liquids.

Are flagella only found in prokaryotic cells?

no, we do see them mainly in prokaryotic cells, but they can be seen in some eukaryotic cells as well

What is/are the main function(s) of the Rough ER?

Aids in protein synthesis, produces new membrane.

What is/are the main function(s) of the smooth ER?

synthesizes lipids, metabolizes carbs, and stores Ca2+ ions

What is/are the main function(s) of the Golgi Apparatus?

It directs processing, protein sorting, and secretion of cellular molecules.

What is the cis golgi?

the receiving side of the golgi apparatus, near the ER membrane

What is the trans golgi?

It is the “sending” side of the golgi apparatus, closest to the plasma membrane

What is/are the main function(s) of the centrosome?

They help to organize microtubules and the cell division process

What are the main components of the Nucleus?

the nuclear envelope, the nucleolus, and chromatin

Describe the Nuclear envelope

It is what bounds the nucleus of eukaryotic cells. Has a lipid bilayer and is perforated with nuclear pores, and its inner surface is supported by nuclear lamina

What is/are the main function(s) of the Nucleolus?

the nucleolus helps produce and assemble the cell’s ribosomes

What is/are the main function(s) of the Chromatin?

chromatin package the long stranded DNA into a smaller, more organized structure

What is/are the main function(s) of the plasma membrane?

seperates the inside of the cell from the outside environment, and also filters what goes in and out of the cell.

What is/are the main function(s) of Ribosomes?

protein synthesis!

What is/are the main function(s) of the Lysosome?

Breakdown of ingested substances, cell macromolecules, and damaged organelles for recycling

What is/are the main function(s) of the Mitochondria?

they produce energy! (ATP)

What is/are the main function(s) of the peroxisome?

Contains enzymes that transfer H atoms from substrates to oxygen, producing H2O2 , which is converted to H2O

What is/are the main function(s) of the microvilli?

in the small intestine, it enlarges the surface area of the cell to facilitate absorption of water and ingested food

What is/are the main function(s) of the Microfilaments?

provides structure support and facilitate cellular transport

What is/are the main function(s) of the Intermediate filaments?

provides mechanical strength and structural stability

What is/are the main function(s) of the Microtubules?

determine cell shape and help with a variety of cell movements (such as intracellular transport of organelles and seperation of chromosomes during mitosis)

What is/are the main components of the cytoskeleton?

microfilaments (actin), intermediate filaments, and microtubles (in increasing roder of thickness)

What is/are the main function(s) of the Cell Wall? (in a plant cell)

provides structural support, and maintains cell shape

What is/are the main function(s) of the chloroplast in a plant cell?

to conduct photosynthesis!

What is/are the main function(s) of the plasmodesmata in a plant cell?

creates cytoplasmic communication channels through the rigid plant cell wall

What is/are the main function(s) of the central vacuole (in a plant cell)?

stores waters, nutrients, waste products, and isolates harmful substances

In an animal cell, what are the components of the endomembrane system?

the ER (rough and smooth), the nucleus, plasma membrane, ribosomes, golgi apparatus, lysosome, and peroxisome

In an animal cell, what is the semiautonomous organelle?

The Mitochondria

In an animal cell, what are the cytoskeletal elements?

The centrosome, and the cytoskeleton (made of microfilaments, int. filaments, and microtubules)

In a plant cell, what makes up the endomembrane system?

the ER (rough and smooth), the nucleus, plasma membrane, ribosomes, golgi apparatus, peroxisome, and the central vacuole

What are the semiautonomous organelles in a plant cell?

the mitochondria and chloroplast

what is the structure of the ER?

extensive network of membrane-bounded tubules and sacs; ER membrane separates lumen from cytosol and is continuous with nuclear envelope

what is the structure of the golgi apparatus?

Stacks of flattened membranous sacs; has polarity (cis and trans faces)

what is the structure of a lysosome?

Membranous sac of hydrolytic enzymes (in animal cells)

what is the structure of a vacuole?

large membrane-bounded vesicle

what is the structure of mitochrondrion?

Bounded by double membrane; inner membrane has infoldings

what is the structure of a chloroplast?

Typically two membranes around fluid stroma, which contains thylakoids stacked into grana

what is the structure of the peroxisome?

Specialized metabolic compartment bounded by a single membrane

Define active transport

the movement of solutes across a membrane (from low to high concentration) with the help of a transport protein

does active transport require energy? if so, in what form?

yes! ATP

what is a histone?

a DNA binding protein

what is a nucleosome?

DNA wrapped two times around the histone

what is ploidy?

the number of chromosomes in the nucleus of a cell

what is the ploidy of humans?

46 (2n=46, 23 from mom and 23 from dad, since humans are diploid!)

what are chiasmata?

the point at which crossing over happens in homologs

what is the centromere?

the protein that holds together sister chromatids until they seperate in anaphase two.

what is the synaptonemal complex?

it is a protein that holds together homologous chromosomes

what holds together sister chromatids?

cohesion proteins

what happens in the G1 phase of interphase?

metabolic activity, organelles grow and duplicate, chromosomes remain UNduplicated, where transcription and translation occurs

what happens in the S phase of interphase?

the synthesis of DNA, results in duplicated chromosomes, growth + metabolic activity

What happens in the G2 phase of interphase?

growth + metabolic activity, prep for cell division (synthesis proteins that help with movement in mitosis)

What is the G0 phase in interphase?

The phase inbetween G1 and S in which inactive cells will go, acts as a “resting”/nonduplicating spot

What happens at the G1 checkpoint?

it decides whether or not the cell is fit to duplicate (any errors in DNA before replication, makes sure the size is right). If it recieves the “go-ahead” signal, the cell can duplicate. If not, it receives the “stop” signal.

What happens at the G2 checkpoint?

it makes sure that the DNA has been correctly duplicated, and that the cell is ready to divide. stop or go signals decide if the cell continues to division.

where does crossing over occur in meiosis?

prophase 1

what does diploid mean?

it means that there are 2 complete sets of chromosomes (forms X)

do all cells contain nuclei?

no, as prokaryotes do not have a nucleus!

why is there a limit to how big or small a cell can be?

there is a limit because the rate of movement for nutrients into cells and waste products out of cells is limited by diffusion

do plant cells contain centrosomes?

no! only animal cells do

What structure of the cytoskeleton does NOT play a role in intracellular movement?

intermediate filaments

In an animal cell, what are the tiny strings that come from each side of a cell and attach to the kinetochores of the chromosomes of a cell during metaphase?

they are microtubules

What process would help a pancreatic cell secrete enzymatic proteins out of the cell?

exocytosis

How does oxygen gas (O2) get into cells for cellular respiration?

Simple diffusion across the membrane

in a Na+/K+ pump, what direction does the Na+ and K+ flow (in/out of cell, high/low conc)?

the Na+ will flow out of the cell, and the K+ will flow into the cell, from a low to high concentration

In metaphase of mitosis, are the chromosomes duplicated or unduplicated?

duplicated!

do daughter cells have duplicated or unduplicated chromosomes after going through mitosis?

unduplicated!