cells

Question 1

characteristics of eukaryotic cells?

Answer 1

fungi, animals, humans, plants. DNA in a nucleus that is bounded by a double membrane. membrane-bound organelles. cytoplasm - region between the plasma membrane and nucleus. eukaryotic cells are generally larger than prokaryotes.

Question 2

characteristics of prokaryote cells?

Answer 2

prokaryotes are bacteria. no nucleus. DNA in an unbound region called the nucleoid. no membrane bound by organelles. cytoplasm bound by the plasma membrane.

Question 3

plasma membrane?

Answer 3

phospholipid and protein cell boundary (integrated proteins). selectively permeable barrier which permits certain materials to enter and certain to exit. transport proteins are often responsible for controlling passage across cellular membranes. in the fluid mosaic model, the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.

Question 4

cytoplasm?

Answer 4

water, biochemical, solutes and organelles that fill the majority of the cell and support.

Question 5

ribosomes?

Answer 5

organelle of RNA and protein that makes protein. protein factories. ribosomes are complexes made of ribosomal RNA and protein. ribosomes carry out protein synthesis in the cytosol (free ribosome) and on the outside of the ER or the nuclear envelope.

Question 6

DNA?

Answer 6

genetic material encoding proteins’ structures.

Question 7

differences between prokaryotes and eukaryotes?

Answer 7

prokaryotes have no nucleus and have no membrane bound organelles, whereas eukaryotes have membrane bound organelles. prokaryotes have 2 RNA in the large subunit and 1 in its small, giving it a smaller overall size. eukaryotes have 3 RNA molecules in the upper sub-unit, giving a greater all size, same in the sub-unit.

Question 8

core four similarities between prokaryotes and eukaryotes?

Answer 8

DNA, ribosomes, plasma membrane, cytoplasm.

Question 9

what is cell theory?

Answer 9

repeated microscopic observations of many organisms. cells are the basic unit of life. cells usually arrise from pre existing cells.

Question 10

who was the first to discover the first live cell?

Answer 10

anton von leeuwenkoek, 1676 - called it an animocule.

Question 11

who discovered the cell wall?

Answer 11

robert hooke, 1665.

Question 12

large cells?

Answer 12

not active, more likely to be used as storage as its hard for it to be metabolically active. large to store nutrients, eggs, adipose. predators large to consume prey. amoeba, paramecium.

Question 13

function dictates structure?

Answer 13

plasma membrane is both outlet and inlet for exchange. need monomers, water, oxygen and electrolytes. dispose of metabolic waste.

Question 14

supply / disposal restrictions?

Answer 14

need enough surface area to service exchange needs. cell size (volume) increases faster than surface area. cells must stay small to supply entire cytoplasm. larger cells don’t do much (egg cells). eggs activated by fertilisation divide into smaller cells.

Question 15

absorption and exchange?

Answer 15

different shapes can improve surface area / volume ratios. cells specialising in absorbing exchange after shape. microvilli.

Question 16

processes?

Answer 16

extend branches from the center of the cell.

Question 17

exons, dendrites?

Answer 17

neuron connections.

Question 18

pedicels?

Answer 18

filter blood in kidneys.

Question 19

stereocilia?

Answer 19

detect movement in the inner ear.

Question 20

cilia?

Answer 20

short, numerous oar like membrane extensions.

Question 21

pseudopodia?

Answer 21

changing membrane shape to crawl.

Question 22

flagellum?

Answer 22

resemble cilia, but few and long.

Question 23

prokaryotes?

Answer 23

unicellular organisms without nuclei, nucleoid present. bacteria, cyanobacteria, archaebacteria. dna coiled but not separated from cytoplasm.

Question 24

eukaryotes?

Answer 24

dna segregated from cytoplasm by a membrane. unicellular organisms and multicellular fungi, plants and animals.

Question 25

surface area?

Answer 25

a decreased surface area to volume ratio decreases a cells ability to exchange with the environment.

Question 26

structure?

Answer 26

phospholipid hydrophobic head and a hydrophobic tail (phospholipid bilayer). two layers hydrophilic top and bottom, hydrophobic center.

Question 27

barrier?

Answer 27

surfaces allow border with H2O outside, cytoplasm inside. center is barrier to hydrophilic ions and polar molecules.

Question 28

the permeability of the lipid bilayer?

Answer 28

hydrophobic (nonpolar) molecules such as hydrocarbons can dissolve in the lipid bilayer and pass through rapidly. hydrophilic molecules including ions and polar molecules do not cross the membrane easily. proteins built into the membrane play key roles in regulating transport.

Question 29

cholesterol?

Answer 29

animal cells, not plants. intermixed with phospholipids. regulates stiffness and flexibility. cholesterol has different effects on cells at different temperatures. at warm temperatures cholesterol limits phospholipids movements. at cool temperatures, cholesterol prevents lipids from becoming packed.

Question 30

proteins?

Answer 30

float and drift in the bilayer. most functions other than the barrier: transport, signaling, etc.

Question 31

transport proteins?

Answer 31

transport proteins allow the passage of hydrophilic substances across the membrane.

Question 32

membrane carbohydrates and cell-cell recognition?

Answer 32

cells recognize each other by binding to molecules. often with extracellular surface carbohydrates. membrane carbohydrates may covalently bond to lipids forming glycolipids or proteins. especially important in signaling and adhesion functions.

Question 33

cytoplasm functions?

Answer 33

most chemical reactions of the cell, position and move the nucleus and other organelles. vary viscosity for a structural report

Question 34

cytoskeleton and functions?

types?

Answer 34

microtubules: tubulin for shape and intracellular transport. provide the framework for major transport. microfilaments: actin for membrane shape, contraction. intermediate filaments: proteins vary, support and strength.

Question 35

microtubules - cilia and flagella?

Answer 35

microtubules control the beating of flagella and cilia.

Question 36

microfilaments and intermediate - microvilli connections?

Answer 36

crosslinked actin provide support connected by a dense network of intermediate filaments.

Question 37

nucleus?

Answer 37

eukaryotes only contains chromosomal dna. nucleoplasm: gelatinous matrix inside. nuclear envelope: double membrane with pores. nucleolus: manufactures ribosomes.

Question 38

endosymbiotic organelles?

Answer 38

eukaryotes only evolved from captured bacteria. at least 2 membranes, own chromosome, and ribosomes. mitochondria: aerobic respiration. (aerobic non-photosynthetic bacterium). chloroplasts: plants and algae only, photosynthesis. (photosynthetic bacterium).

Question 39

mitochondria: chemical energy conversion.

Answer 39

found in nearly all eukaryotes, site of aerobic respiration. smooth outer membrane and a folded inner membrane.

Question 40

chloroplast: the capture of energy light?

Answer 40

site of photosynthesis, found in leaves and green organs of plants and cells of algae. key components: thylakoids/granum, outer and inner membrane and inner membrane space, stroma.

Question 41

core 4?

Answer 41

dna, ribosome, plasma membrane, cytoplasm.