101 Molecules And Cells

Front 1

Heterochromatin

Back 1

Tightly packed chromatin, non expressed

Front 2

Euchromatin

Back 2

Loosly packed, expressed

Front 3

Central dogma (crick)

Back 3

DNA --> RNA --> Protein

Front 4

Reading frame

Back 4

The possible points where transcription can begin,

3 possible frames, normally only one is usable

Front 5

Sequences always start with...

Back 5

AUG methionine

Front 6

Ends a sequence

Back 6

STOP codon

Front 7

The genetic code is... (5)

Back 7

- degenerative

- universal

- optimised to minimise effects of mutations

- 3rd postion often doesn't matter

- 1st position change result in similar chemistry

Front 8

Bacterial dna is... (4)

Back 8

- Circular

- fairly open structure

- packed by supercoiling + wrapped around proteins

- genes are generally switched on as default

Front 9

How does RNA polymerase begin transcription?

Back 9

Sigma subunit binds to its specific promoter region, upstream of template sequence. The sigma unit detaches and the polymerase begins transcribing

Unwinding begins at -10 (where there's lots of A and T) then synthesis starts at +1.

Front 10

Sense strand

Back 10

Meaningful sequence, actual code for the peptide chain

Front 11

Antisense strand

Back 11

The template strand, used to build rna stand on

Front 12

Transcription bubble

Back 12

The area where dna is unwound thfn rewound and rna produced

Front 13

What proteins and how do they hinder/help transcription

Back 13

Aplha helix proteins can sit in the major groove. They usually bind to dna in 2 places to specific sequences of 10-12bp.

Front 14

Histone and nucleosomes

Back 14

Histone are proteins that help pack dna, it attaches to dna to form nucleosomes, which then form 30nm thick fibres

Front 15

4 types of atp dependant remodelling

Back 15

- nucleosome sliding

- removal of nucleosome

- create a remodelled, easily accessible state

- replacement of histones

Front 16

Methylation

Back 16

Addition of methyl group (e.g. 5 methyl C)

Promotes tighter packaging

Associated with inactive dna

Front 17

Acylation

Back 17

Attachment of a lipids side chain

Promotes opening + gene expression

Front 18

In bacteria, dna replication is

Back 18

Bidirectional

Involves 3 polymerases

Front 19

In eukaryotes ____ and ___ are responsible for division in cytokinesis and ___ for separation of chromosomes. (Opposite in bacteria)

Back 19

Actin

Myosin

Microtubules

Front 20

Eukaryotes have ___ origins of ___ , while bacteria have ___

Back 20

Multiple

Replication

One

Front 21

MerB is an __ __ and drives ___

Back 21

Actin homolgue

Segregation of replication origin

Front 22

FstZ is a ___ ___ and drives ___

Back 22

Tubulin homologue

Division

Front 23

Condensin and cohesion proteins

Back 23

Aid supercoiling of chromatids in mitosis

Front 24

In plants cell replication there is no ___ ___. Instead a ____ ___ grows across the cell.

Back 24

Pinching off

New membrane

Front 25

Cyclins

Back 25

Proteins whose concentration rise and fall throughout the cell cycle. Points of highest concentration generall indicate boundaries between stages.

Front 26

Checkpoint

Back 26

Points in cell cycle where info must be accumulated before progressing to the next stage. Aided by cyclins.

Front 27

Cyclin dependant kinase (cdk)

Back 27

In the presence of cyclin, Phosphotylates other proteins signalling progression past check point. Must be active for next stage

Front 28

P53

Back 28

Triggers apoptosis if cell is irreversibly damaged.

P53 is damaged or not present in cancerous cells.

Front 29

Cytokinin

Back 29

A compound that promotes cell division and inhibits aging in plants

Front 30

Condensin

Back 30

The complex pf proteins involved in the compaction of chromosomes onto the proteim scaffold. The bacterial equivalent is SMC in the nucleoid.

Front 31

Karyotype

Back 31

The array of chromosomes in an individual. Arranged by length, shape, and centromere location.

Front 32

Cohesin

Back 32

Protein complex that regulates separation of chromosomes in mitosis or meiosis

Front 33

APC

Back 33

Anaphase promoting complex

Found at spindle checkpoint

Front 34

MPF

Back 34

Maturation/Mitosis/Mphase promoting factor

Stimulates mitotic and meitotic phases

Front 35

The 3 checkpoints

Back 35

- G1/M (cdc2 / G1 cyclin) Decides whether or not to divide. Damage to DNA, starvation or lack or growth factors can stop replication.

- G2/M (cdc2 / mitotic cyclin) represents commitment to mitosis and assesses success of DNA replication

- Spindle (APC) ensures all chromosomes are attached to spindle in preparation for anaphase

Front 36

Kinetochore

Back 36

Disc like proteins at the centromere that function as an attachment sitegor spindle

Front 37

Septation

Back 37

Formation of septum (new cell wall and membrane) in binary fission. Facilitated by FtsZ

Front 38

In the cell cycle, the M Phase consists of ___ (division of the nucleus) and ___ (cell divides intontwo daughter cells)

Back 38

Mitosis

Cytokinesis

Front 39

pinocytosis

Back 39

when a cell takes in liquid (or moves out)

Front 40

phagocytosis

Back 40

movement of fragments of organic matter in/out of a cell

Front 41

lipid rafts

Back 41

Areas of the plasma membrane that are enriched with cholesterol and sphingolipids.

Contains raft associated proteins.

Front 42

What is the difference between integral and peripheral membrane proteins

Back 42

integral - proteins that protrude through the membrane. Often have glycan groups on external regions.

Peripheral - associated with the internal surface of the membrane

Front 43

The 3 fibres that make up the cytoskeleton

Back 43

Actin filaments (Microfilaments)

Microtubules

Intermediate filaments

Front 44

Intermediate filaments are...

Back 44

the most durable element of the cytoskeleton. They provide structural stability and anchor the cell.

(e.g. keratin, neurofilaments)

Composed of protein tetramers

Front 45

microtubules are....

Back 45

largest element with the shortest half life.

Responsible for movement of material in the cell, separation of chromosomes an cytoplasm organisation.

Hollow tubes constructed from 13 protofilaments made up of alpha and beta tubulin (globular protein)

Front 46

actin filaments are...

Back 46

Made up of two strands of actin, a globular protein.

They are responsible for cell contraction, movement, extracellular extension formation and pinching off.

Act as anchors for enzymes and ribosomes.

Concentrated below the plasma membrane.

Front 47

4 components required for moving materials in cells

Back 47

1) Vesicle or organelle to be transported

2) Motor proteins that provide energy driven motion

3) a connector molecule to connect the vesicle to the motor molecule

4) microtubules on which vesicles can move like a train track

Front 48

the two motor proteins

Back 48

Kynesin - uses ATP to move vesicles to the cell periphery (to the positive end of actin)

Dynein - to the inside (to the -ve end)

Front 49

cells crawl by ____ ___ of ___ at the leading edge which is then stabilised by _____. Forward movement is achieved though action of the protein ____.

Back 49

rapid polymerisation of actin

microtubules

myosin

Front 50

eukaryotic flagella have a _____ structure. Cilia are similar but ___

Back 50

9+2

shorter

Front 51

animal cells excrete an _____ ____ which is made of and elaborate mixture of _____

Back 51

extracellular matrix (ECM)

glycoproteins

Front 52

the centrosome is known as the ____ ____ ___ and is the ___ ____, often found surrounding a pair of ____. Plants and fungi lack ___ but still have ___

Back 52

microtubule organising centre

pericentriolar material

centrioles

centrioles

centrosomes

Front 53

Chaperone proteins....

Back 53

help other proteins fold correctly, are found in virtually every studied organism and increase in number when cells are exposed to high temperatures.

Front 54

Domains

Back 54

A functionally distinct part of a proteins tertiary structure

Front 55

motifs

Back 55

How elements of a proteins secondary structure interact and fold. (e.g. helix-turn-helix or β-α-β motifs)