Cell Bio Flashcards

1
Q

Membrane function

A

holds internal content of the cell separate from the outside and regulate what gets into and out of the cell.
Water, gases (O2, CO2), small noncharged or non-polar molecules pass through NA+, large molecules like sugar cannot

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2
Q

phospholipid bilayer

A
  • two layers of phospholipids, flexible structure describes a fluid mosaic model
  • cholesterol is an integral part of the cell membrane, is in the hydrophobic portion keeps the membrane flexible
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3
Q

Membrane proteins

A

associated with the membrane - some are external, some are on the inside, and some are transmembrane proteins (across)

function

1) acting as receptors
2) channels or pumps for ions and other material to cross the membrane
3) signaling across the membrane

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4
Q

Passive movements

A

diffusion

osmosis

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5
Q

diffusion

A

the tendency of molecules to spread from areas of high concentration to areas of low concentration in order to reach equal concentration throughout- the process is driven by the concentration gradient

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6
Q

Osmosis

A

movement of water across a cell membrane from high concentration to low areas

thing of salt

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7
Q

isotonic

A

equal salt concentration inside and outside of cells

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8
Q

hypotonic

A

salt concentrations outside the cell are less than those inside the cell,

water moves into the cell to reduce the internal salt concentration
the cell will swell and may eventually burst

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9
Q

Hypertonic

A

salt concentrations outside the cell are greater than those inside the cell.

water moves out of the cell to increase the internal salt concentration, the cell will shrink

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10
Q

active movement

A

requires cellular energy

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11
Q

Active transport

A

involves transmembrane protein acting as “pumps”- ATP is required - into the cell or “pumping out” materials such as ions to maintain unequal concentration such as K+ or Na+

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12
Q

Endocytosis

A

bringing something into the cell across the membrane

  • Receptor-mediated endocytosis
  • phagocytosis
  • pinocytosis
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13
Q

receptor-mediated endocytosis

A

the molecule binds to a receptor on the surface of the cell- that triggers the receptors and the material bound to it to be brought in through the cell membrane to the inside of the cell in a vesicle

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14
Q

Phagocytosis

A

cell engulfs solid material (white blood cells ingesting a bacteria)- bring it in through the cell membrane and breaks it down

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15
Q

Pinocytosis

A

cell engulfs and brings in liquid material

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16
Q

exocytosis

A

moving something in vesicle from the inside of the cell to be released to the outside

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17
Q

Cytoplasm

A

the fluid or gel inside the cell (cytosol) and the various organelles

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18
Q

Ribosomes

structure and function

A

very small made up of 2 circular subunits-found free in the cytoplasm or attached to the round endoplasmic reticulum

the function is to make protein

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19
Q

Endoplasmic reticulum

structure and function

A

a ‘stack’ of folded interconnected membranes-start at the edge of the nuclear membrane

function- two type

rough: covered with ribosomes=make protein
smoot: make lipids

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20
Q

Golgi Apparatus

structure and function

A

a series of stacked and folded membranes (similar to but smaller than the Er)

function

1) adding sugars to the molecules
2) packaging material for movement to another part of the cell or release from the cell- the material is placed in a vesical and moved elsewhere within the cell or released by exocytosis

21
Q

Lysosomes

structure and function

A

small, rounded, membrane-bounded structure

function- contains digestive enzymes and other molecules- breaks things ingested by the cell

22
Q

Vacuoles

A

a membrane-bounded “bubble” within a cell that stores something (ex. food vacuole)

23
Q

Mitochondria

structure and function

A

kidney-shaped- contain highly infolded internal membranes called cristae- this creates additional surface areas and are sites for cellular respiration to take place and the ATP synthase to function. They have their own DNA which is passed from mother to offspring

function- production of ATP, cellular energy

24
Q

Chloroplasts

A

specialized structure for carrying out photosynthesis- contains chlorophyll and membrane systems including the thylakoid membrane

25
Q

Cytoskeleton

A

group 3 different protein strands with a different function:
1) intermediate filaments- internal “skeleton” providing structure for the cell
2) microtubules or tubulin- the intracellular movement of materials from places to places within the cell, are found in the cilia and flagella, and form the mitotic spindle involved in mitosis and meiosis
3) microfilaments- thin filaments of actin (and myosin) for movements of the cell itself such has amoeboid motion.
microtubules are also found in cilia and flagella

26
Q

Nucleus

nuclear membrane

A

the membrane that surrounds the chromosomes-in it is nuclear pores-small holes which allow the material to pass from the nucleus to the cytoplasm

27
Q

Nucleus

chromosome

A

a strand of DNA and protein (chromatin)- the DNA exists in a highly coiled state-supercoiled- the proteins (histones) pack the DNA into a small space and are also involved in controlling gene expression

28
Q

Mitosis

general concept

A

occurs in the body (somatic cells) mitosis is replication fo the nucleus.

29
Q

Prophase

A

cell prepares to divide: the nuclear membrane breaks down and the spindle apparatus forms

30
Q

Metaphase

A

two sets of chromosomes line up in the middle of the cell

31
Q

anaphase

A

two sets of chromos move apart to the opposite ends

32
Q

telophase

A

nucleus reforms and the spindle apparatus break down

33
Q

interphase

A

the period between cells mitoses

34
Q

The cell cycle

A

refers to the various phases a cell goes through-Mitosis (M) is one of them-a cell spends most of its time in the growth (G), or DNA duplication (S) phase of the cell cycle

35
Q

Meiosis

general concepts-

A
  • occurs in reproductive organ cells (germ cells) sperm and egg
  • normal body cells (somatic cells) have 2 chromosomes in pairs-condiction referred to as diploid and indicated by 2n
  • Meiosis results in the formation of germ cells which have single chromosomes- a condition referred to as haploid and indicated by 1n (23)
36
Q

cytokinesis

A

replication of the rest of the cell (remember mitosis is only the nucleus)- cytoplasm and organelles

37
Q

Cell Metabolism

general concepts

A

metabolism is all the various biochemical reactions taking place
anabolism- build things up from smaller components or subunits
catabolism - breaking molecules down

38
Q

Enzymes

general concepts

A

carry out all the metabolic reactions in the cells, each enzyme specific for a reaction and repeating the reaction

  • catalyst lower the energy needed for the reaction to happen
  • substrate-substance that enzyme acts upon, depends on the substrate shape and enzyme’s active site
39
Q

Coenzymes and Cofactors

A

extra pieces needed by some enzyme to function, two types

  • Coenzymes: organic (thiamine, riboflavin, niacin) mainly vitamins (fat-soluble and water soluble)
  • Cofactors: inorganic (iron, zinc, magnesium, copper) a mineral
40
Q

Fat-soluble vitamins

A

A, E, D, and K; taking fat-soluble vitamins in high amounts can lead to toxicity to the liver, as they are not excreted well

41
Q

water-soluble vitamins

A

C, also known as ascorbic acid, various B vitamins (B1, (thiamine) B2 (riboflavin), B3 (niacin), B6, B7, B12)

the disease resulting from a deficiency in vitamin C is known as scurvy

42
Q

Control activity of the enzyme

A

amount of product produced act as a single that will bind to and shut down the enzyme, this is known as the feedback inhibiting

43
Q

Aerobic Respiration

list steps

A

With oxygen

  • glycolysis- glucose is broken down into 2 pyruvic acids, 2 ATP is made
  • Kreb’s Cycle- citric acid cycle- the 2 pyruvic is broken down (from Glycolysis) into CO2, 2ATP, and NADH and FADH2 are also produced
  • Oxidative phosphorylation- electron transport chain, oxidative-reduction happens here, most ATP made, kind oxygen (H+), water is waste product
44
Q

Anaerobic Respiration

Fermentation

A

No O2,

  • terminal acceptor- instead of oxygen in the electron transport chain, it is sulfur, H2S is produced instead of water
  • Fermentation- involves glycolysis (and few steps) and does not go onto Kreb’s cycle and Electron transport chain. the least efficient process than aerobic, and 2 ATP result, and alcohol and acetic acid are formed
45
Q

Photosynthesis

general concept

A

CO2 and H2O are input and O2 is the waste product

- Light reaction- light is required, the goal is to generate ATP

46
Q

Photosynthetic Pigments

A

the Key molecule is this process chlorophyll, accessory pigments are also involved- they trap the energy form different wavelengths of sunlight

47
Q

Photosynthesis, ATP production

A

water is split- (O and H+) - the protons are passed through an electron transport chain to generate ATP while Oxygen is left as a waste product

48
Q

Dark reaction (Calvin-Benson cycle)

A

light is not required for this-The ATP generated in the light reaction is now used (along with CO2) to make sugar and other molecules

49
Q

Chemosynthesis

A

an unusual form of anabolism only carried out by certain bacteria “photosynthesis without the sun”, involves the energy of certain chemical reaction (NO2-NO3)
example: communities found miles under the surface around undersea volcanoes, bacteria get the energy from the minerals coming out of the volcanoes