Cells - lecture 2

Question 1

cells

Answer 1

smallest unit of life that can function independently

Question 2

who coined the term “cells?”

Answer 2

Robert Hooke (1660)

Question 3

cell theory

Answer 3

all organisms are made up of cells; the cell is the base unit for all life; all cells come from pre-existing cells

Question 4

what do all cells contain?

Answer 4

DNA, RNA, ribosomes, proteins, cytoplasm, and cell membrane

Question 5

why are cells so small?

Answer 5

everything is transported across the cell membrane and the smaller the object, the smaller surface area to volume ratio

Question 6

what are the two types of cells

Answer 6

prokaryotic and eukaryotic

Question 7

prokaryotic cells

Answer 7

no membrane-bound nucleus (nucleoid), small with few structures

Question 8

prokaryotic domain

Answer 8

bacteria and archaea

Question 9

Eukaryotic cells

Answer 9

membrane-bound nucleus, internal structures bound by membranes called organelles

Question 10

eukaryotic domain

Answer 10

Eukarya

Question 11

Prokaryotes consist of

Answer 11

cell wall (sometimes a capsule), cell membrane, cytoplasm, and nucleoid (DNA)

Question 12

Eukaryotes consist of

Answer 12

one or more cells, animal and plant cells, made up of organelles (‘little organs’) and each has its own function(s)

Question 13

cell membrane

Answer 13

all cells have one, made of phospholipids, phospholipid bilayer (phospholipid head and fatty acid tails)

Question 14

what would happen if phospholipids were added to water?

Answer 14

1. form a layer on the surface
2. form spherical droplets (single layer)
3. orient so the heads interact with the water and tails point away from the water (double layer)

Question 15

What can freely pass through cell membranes

Answer 15

lipids and small, non-polar molecules

Question 16

what cannot freely pass through cell membranes

Answer 16

ions and polar molecules (due to hydrophobic interior)

Question 17

Diffusion

Answer 17

the cell has no control over the movement of water and moves until equilibrium is reached

Question 18

Fluid mosaic - what are cell membranes made up of

Answer 18

Sterols, phospholipids, proteins, and enzymes

Question 19

what do the sterols and phospholipids provide for the cell membrane?

Answer 19

structural support

Question 20

What do proteins provide for the cell membrane?

Answer 20

transport, adhesion, recognition, and receptor

Question 21

What do enzymes provide for the cell membrane?

Answer 21

facilitate chemical reactions

Question 22

Cell wall

Answer 22

plant cells and bacteria, made of carbohydrates which are structural and protective

Question 23

Inside the cell

Answer 23

cytoplasm, organelles, and proteins

Question 24

what does the nucleus contain?

Answer 24

enclosed by a membrane; contains a cells DNA (genetic material); control center; contains the nucleolus

Question 25

what does the nucleolus do

Answer 25

assemble components of ribosomes - parts come together once they leave the nucleus to become ribosomes in the cytoplasm

Question 26

Ribosomes

Answer 26

small (no membrane) - assembles amino acids into proteins

Question 27

Endoplasmic Reticulum (ER)

Answer 27

network of sacs and tubules which make lipids and proteins

Question 28

Rough ER

Answer 28

make proteins and studded with ribosomes (rough appearance)

Question 29

Smooth ER

Answer 29

make lipids and detoxify drugs and poisons

Question 30

Vesicles

Answer 30

Transport and store - consist of small sacs

Question 31

Golgi apparatus

Answer 31

Flat sacs and process proteins by folding (makes them functional)

Question 32

Digestive organelles

Answer 32

Lysosome, Vacuole and Peroxisome

Question 33

Lysosome

Answer 33

Dismantle and digest damaged/old organelles and debris

Question 34

External functions of lysosome

Answer 34

tail of frog and the head of sperm to help break through the egg wall

Question 35

Vacuole

Answer 35

Dismantle and digest organelles and act as water storage/protect agains turgor pressure

Question 36

Peroxisome

Answer 36

dispose of toxic substance

Question 37

Chloroplast

Answer 37

where photosynthesis occurs and contain their own DNA and ribosomes

Question 38

what are chloroplasts made of

Answer 38

Membrane - inner and outer, stroma, thylakoids, and grana

Question 39

stroma

Answer 39

enzyme rich fluid

Question 40

thylakoids

Answer 40

flattened sacs within stroma

Question 41

grana

Answer 41

interconnected stacks of thylakoids

Question 42

Mitochondria

Answer 42

powerhouse of the cell, extract energy from food, and contain their own DNA and ribosomes

Question 43

What are mitochondria made up of

Answer 43

inner and outer membrane and Cristae

Question 44

cristae

Answer 44

folds of inner membrane which increase surface area of mitochondria

Question 45

Endosymbiosis theory

Answer 45

Evidence suggests that mitochondria and chloroplasts were once free-living organisms (bacteria)

Question 46

Why do we think m and c were free-living organisms?

Answer 46

Similar in size, shape and membrane structure as some types of bacteria; double membrane: lysosome/vacuole; replicate via binary fission as bacteria do; photosynthetic pigments and cyanobacteria; and DNA shows a close relationship

Question 47

DNA close relationships with mitochondria and chloroplasts

Answer 47

Mitochondria to aerobic bacteria and chloroplasts to cyanobacteria

Question 48

How does the cytoskeleton contribute to the cell

Answer 48

structural and movement

Question 49

3 components of the cytoskeleton

Answer 49

microfilament, intermediate filament, and microtubules

Question 50

Microfilament

Answer 50

composed of actin, stretching and compression (movement)

Question 51

intermediate filament

Answer 51

maintain cell shape

Question 52

microtubules

Answer 52

composed of tubular, movement of proteins and organelles, and important in cell division

Question 53

Centrosomes contain

Answer 53

centrioles

Question 54

Cilia and flagella

Answer 54

allow a cell to move

Question 55

cilia

Answer 55

shorter and lots of them

Question 56

flagella

Answer 56

longer and 1-2 of them

Question 57

How do plant cells communicate?

Answer 57

plasmodesmata

Question 58

plasmodesmata

Answer 58

channels that connect adjacent cells - cytoplasm of one cell can interact with adjacent cell's cytoplasm

Question 59

how do animal cells communicate?

Answer 59

Can secrete a matrix that holds cells together (cells are not in direct contact with one another) and form junctions or direct contact

Question 60

Tight junction

Answer 60

cells are fused together (impermeable), "blood-brain barrier", and lipid-soluble drugs can still pass

Question 61

anchoring junction

Answer 61

linking intermediate filaments together

Question 62

gap junction

Answer 62

protein channel that links cytoplasm of adjacent cells and analogous to the plasmodesmata