Biology Ib Revision- Cells

Front 1

Cell Theory

Back 1

-All living things made out of cell
-Cells are the smalles unit of life
-Existing cells have come from other cells

Front 2

Muscle Cell

Back 2

Challenges the idea that a cell have one nucleus

Front 3

Fungal cell

Back 3

Challenges the idea that a cell is a single unit

Front 4

Protoctista

Back 4

Challenges the idea that a cell is specialized to a single function. Yet, the protoctista can carry out all the functions of life.

Front 5

Mitosis

Back 5

A process of cell replication in eukaryotes

Front 6

Binary fission

Back 6

A process of cell replication in prokaryotes

Front 7

Similarities of plant and animal cells

Back 7

-Both have nucleus with cytoplasm around them.
-Nucleus is colorless.
-Cytoplasm is enclosed with plasma membrane (too thin to see in light microscope)

Front 8

Differences of plant and animal cells

Back 8

-Plant cells have cellulose wall outside their plasma membrane
-Plant cells have chloroplast
- Plant cells have fixed shapes, usually rather irregular and animal cells are able to change shape, usually rounded.

Front 9

Unicellular organisms

Back 9

Some organisms consist of only one cell. This cell therefore has to carry out all the functions of life. The structure of the single cells of unicellular organism is therefore more complex than most of the cells of multicellular organisms.

Front 10

Functions of life (things that all organisms must do to survive)

Back 10

-Nutrition
-Metabolism
-Growth
-Sensitivity
-Homeostasis
-Reproduction

Front 11

Stem cells

Back 11

Cells that have the capacity to self-renew by cell division and to differentiate. Present in many human tissues including bone narrow, skin and liver. They give some human tissues considerable powers of repair and regenerate.

Front 12

Prokaryotic cells

Back 12

First organisms to evolve on Earth and they still have the simplest cell structure. Bacteria are prokaryotes (small, unicellular and found everywhere).

Front 13

Eukaryotic cells

Back 13

An organism which has more complex structure than Prokaryotic cells.

Front 14

Structure of prokaryotic cells (general)

Back 14

- general size is around 1-2 um
- no membrane bound organelles
- no true nucleus with a nuclear membrane
- ribosomes are smaller than eukaryotic cells

Front 15

Structure of prokaryotic cells (cell wall)

Back 15

- always present
- composed of peptidoglycan
- protects the cell
- maintain its shape
- prevents cell from bursting

Front 16

Structure of prokaryotic cells (Cytoplasm)

Back 16

- plasma membrane contains fluid
- water with many dissolved substances
- contains many enzymes
- contains ribosomes

Front 17

Structure of prokaryotic cells (ribosomes)

Back 17

- 70S ribosomes
- smaller than eukaryotic ribosomes which are 80S
- synthesizes proteins

Front 18

Structure of prokaryotic cells (plasma membrane)

Back 18

- thin layer composed of phospholipids
- can pump substances in our out by active transport
- produces ATP

Front 19

Structure of prokaryotic cells (nucleoid)

Back 19

- region of cytoplasm containing the genetic material (DNA)
- DNA molecule is circular and naked
- smaller amount of DNA compare to eukaryotes

Front 20

Structure of prokaryotic cells (flagella)

Back 20

- corkscrew shape, sticking out from the cell wall
- solid and inflexible

Front 21

Structure of prokaryotic cells (Pili)

Back 21

- protein filaments sticking out from the cell wall
- used for cell to cell adhesion (cling or stick)
- used when two cells are exchanging DNA (during conjugation)

Front 22

Structure of eukaryotic cells (general)

Back 22

Have a nucleus and organelles in the cytoplasm with single or double membranes. Each organelles has different structures and functions.

Front 23

Structure of eukaryotic cells (Nucleus)

Back 23

- nuclear membrane is double and has pores
- uncoiled chromosomes (Chromatin) are spread through the nucleus
-Nucleus store almost all genetic material of the cell

Front 24

Structure of eukaryotic cells (rER) - Rough endplasmic reticulum

Back 24

- contains cisternae (flattened membrane sacs)
- ribosomes attached to outside cisternae
- synthesizes protein for secretion of cell

Front 25

Structure of eukaryotic cells (Golgi apparatus)

Back 25

- contains cisternae, but not as long as the ones in rER and do not have rybosomes attached to it
- process proteins brought in vesicles from rER

Front 26

Structure of eukaryotic cells (Lysosomes)

Back 26

- approximately spherical with a single membrane
- formed from Golgi vesicles
- contains high concentration of protein
- contains digestive enzymes

Front 27

Structure of eukaryotic cells (mitochondria)

Back 27

- contains cristae
- contains fluid called the matrix
- shape is usually spherical or ovoid
- produce ATP for the cell by aerobic cell respiration

Front 28

Structure of eukaryotic cells (free ribosomes)

Back 28

- appear as dark granules in cytoplasm
- not surrounded by membrane
- same size as ribosomes
- synthesizes protein

Front 29

Phospholipids bilayer

Back 29

- essential components of membrane
- have two regions with different properties
- hydrophobic (two hydrocarbon tails, not attract to water)
- hydrophilic (a phosphate head, negatively charged, attracted to water)

Front 30

Structure of membrane and its function (phospholipid bilayer)

Back 30

- hydrophobic layer acts as a barrier to all but the smallest molecules (oxygen&carbon dioxide)
- phospholipids can exchange position in the horizontal plane but not the vertical

Front 31

Structure of membrane and its function (integral proteins)

Back 31

usually span from one side of phospholipid to the other

Front 32

Structure of membrane and its function (peripheral proteins)

Back 32

- proteins sit on the surfaces
- slide around the membrane very quickly and collide with each other but can never flip from one to another
- proteins inside the plasma membrane are involved in maintaining the cell's shape
- may also be enzymes

Front 33

Structure of membrane and its function (glycoproteins)

Back 33

- involved in cell recognition which is part of the immune system
- can also act as receptors in cell signaling such as with hormones

Front 34

Structure of membrane and its function (cholesterol)

Back 34

- binds together lipid in the plasma membrane reducing its fluidity as conferring stability

Front 35

List of the membrane proteins

Back 35

- channel protein
- receptor proteins
- enzymes
- electron carriers

Front 36

Membranes - Channel Protein

Back 36

- span the membrane from one side to the other
- allow the movement of large molecules across the plasma membrane

Front 37

Membranes - Receptor proteins

Back 37

- detect hormones arriving at cells to signal changes in function
- may be involved in other cell and substance recognition as in the immune system

Front 38

Membranes - Enzymes

Back 38

- integral in the membrane

Front 39

Membranes - Electron carriers

Back 39

- seen in photosynthesis and respiration in oxidation/ reduction reactions

Front 40

Diffusion

Back 40

passive movement of particles from a region of high concentration to a region of low concentration

Front 41

Osmosis

Back 41

passive movement of water molecules from a regions of lower solute concentration to a region of higher solute concentration