Ch. 4.1 - Cellular Structure

Question 1

major cellular functions (4)

Answer 1

• genetic control
• manufacture and digestion
• energy processing
• structure support, movement, and communication

Question 2

endomembrane system includes (6)

Answer 2

nuclear envelope, ER, golgi apparatus, lysosomes, vacuoles, plasma membrane

Question 3

endoplasmic reticulum (5)

Answer 3

• smooth or rough
• produces enzyme for synthesis of lipids, oils, phospholipids, and steroids
• produces enzymes that process drugs, alcohol, toxins, etc
• stores Ca+
• manufactures more membranes

Question 4

golgi apparatus (4)

Answer 4

• finishes, sorts, and ships cell products
• Molecular Warehouse and Processing Station
• modifies protein sugars, adds phosphate markers
• vesicles that enter GA mature as they cross stacks from receiving to shipping end

Question 5

lysosomes (5)

Answer 5

• digestion and recycling
• are membrane enclosed sac of digestive enzymes
• may contain up to 50 different digestive enzymes
• have an acidic interior (pH 4.5-5)
• involved in membrane repair and cell signalling

Question 6

journey of a lysosome (5)

Answer 6

• made by rough ER
• processed in GA
• fuse with food vacuoles and digest food
• destroy bacteria
• engulfed by white blood cells or fuse with other vesicles containing damaged organelles or other materials

Question 7

creation of a lysosome (4)

Answer 7

• transport vesicle (contain inactive hydrolytic enzymes) goes to GA
• lysosome engulfing damaged organelle or engulfment of particle
• food vacuole
• digestion

Question 8

peroxisomes (4)

Answer 8

• don’t originate from the endomembrane system (relationship is still unknown)
• break down fatty acids in liver and detoxify alcohol with the end product of H2O2
• other enzymes then convert the hydrogen peroxide to water
• due to toxicity of the products in peroxisomes = why they’re not part if the regular endomembrane system

Question 9

vacuoles (4)

Answer 9

• digestion and osmotic regulation
• large water containing vesicles
• contractile vacuoles help eliminate water
• in plants vacuoles love digestive functions, may contain cell pigments or poisons that protect the plant

Question 10

mitochondria (4)

Answer 10

• double membrane = 2 internal compartments
• intermembrane space and mitochondrial matrix
• folded inner membrane form cristae
• matrix contains mitochondrial DNA, ribosomes and enzymes for cellular respiration

Question 11

chloroplasts (4)

Answer 11

-double outer membrane = 2 internal compartments
-intermembrane space and stroma
-thylakoids = 3rd membrane - inside of which is the thylakoid space
>thylakoids contain chlorophyll

Question 12

endosymbiosis (2)

Answer 12

• one theory for how mitochondria and chloroplasts came into existence within eukaryotic cells
• endosymbiotic theory states that chloroplasts and mitochondria originated as undigested bacteria in eukaryotic cells

Question 13

rationale for endosymbiosis (3)

Answer 13

• mitochondria and chloroplasts contain their own DNA and ribosomes, which are more similar to these prokaryotes
• they have double membranes - could be explained by phagocytosis
• they divide independently from the cell

Question 14

cytoskeleton - cellular highway (2)

Answer 14

• provides structural support and functions in cell motility and regulation
• composed of 3 basic parts: microfilaments, intermediate filaments, microtubules

Question 15

microfilaments (3)

Answer 15

• solid rods of mostly actin protein arranged in a twisted double chain
• form a 3D network just inside the plasma membrane
• support the cells shape and interact with the thicker myosin filaments to cause muscle contraction

Question 16

intermediate filaments (3)

Answer 16

• bigger than microfilaments and smaller than microtubules
• made from a variety of fibrous proteins that coil together into thicker cables
• reinforce cell shoe and anchor certain organelles, like the nucleus

Question 17

microtubules (4)

Answer 17

• largest components of the cytoskeleton
• made up of tubulin protein (forms a hollow tube)
• help maintain cell’s shape and combined with motor proteins act as tracks for organelles to move along within the cell - the transport highway of cells
• very important in centrioles, cilia, and flagella

Question 18

extracellular matrix (2)

Answer 18

-animal cells excrete an extracellular matrix of glycoproteins and collagen that helps hold tissues together and support the plasma membrane
-EM of glycoproteins and collagen may bind to integrin
proteins that span the membrane and attach to microfilaments on the inside of the cell

Question 19

what do sperm and cilia have in common (5)

Answer 19

-past 50 years decline in sperm counts and qualirt
-phthalates (plasticizers) are hormonally active and mess with sex hormones and sperm quality in rats
-several studies show that normal levels of human exposure to phthalates is correlated with lower sperm counts and quality
-no dynein protein = primary ciliary dyskinesia
>cilia and flagella cannot bend so lungs can’t be cleared and sperm can’t swim

Question 20

how are animal cells connected to each other?

Answer 20

for a tissue to be a tissue, there must be communication between the cells that are a part of it

Question 21

3 types of cell junctions

Answer 21

• tight (very close and “knit” together by proteins)
• anchoring (cells riveted together with keratin proteins anchored in the cytoplasm (desmosomes))
• gap (communicating) protein lined pores connect cells allowing ions to flow through

Question 22

plant cell walls (3)

Answer 22

• cell walls of plants must have “holes” in them to allow for intracellular communication in plant tissues
• there “holes” are called plasmodesmata or plasmodesma (sing.)
• plasma membrane and cytoplasm of the cells extend through the plasmodesmata