LECTURE 4 WHY AND HOW CELLS DIVIDE Flashcards Preview

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Flashcards in LECTURE 4 WHY AND HOW CELLS DIVIDE Deck (24)
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1

Recall cell structures from last time

•Membranes
•Nucleus (and nucleolus)
•Chromosomes
•Ribosomes
•Endoplasmic Reticulum (RER and SER)

2

Golgi Apparatus

•Polarized stack of membranes
•Enzymes modify proteins from ER
•Add & modify sugars

•Material moves between stacks via transport vesicles

•Many final destinations

3

Protein synthesis occurs in different places

Cytoplasmic proteins

•Made of free ribosomes in the cytoplasm
•Proteins are soluble (hydrophilic)

4

Protein synthesis occurs in different places

Membrane proteins and secreted proteins

•Made on ribosomes bound to the ER
•Sorted in the Golgi apparatus
•Membrane proteins are hydrophobic or amphipathic
•Secreted proteins can be either hydrophilic or hydrophobic (or amphipathic!)

5

Lysosomes: Acidic organelles

Digest food & polymers to recycle monomers

Phagocytosis
Autophagy

6

Mitochondria:

makes ATP (energy for the cell)

7

Cytoskeleton: support for the cell

•Microtubules (tubulin)
•Microfilaments (actin)
•Intermediate Filaments (keratins +)

8

How do cells divide?
Bacteria and mitochondria

•Binary fission
•One small circular chromosome is copied
•Cell pinches between DNA molecules
•Cytoplasm/matrix divides

9

How do cells divide?
Eukaryotic cells

•Many long linear chromosomes
•Need to evenly divide DNA so daughter cells get all info •After DNA is divided, cytoplasm and organelles divide

10

Eukaryotes have two types of cell division

Growth and repair = MITOSIS

Two identical daughter cells

11

Eukaryotes have two types of cell division

Reproduction = MEIOSIS

4 non-identical haploid cells from a diploid cell (sperm, eggs)

12

THE CELL CYCLE

INTERPHASE:

G1 – grows, make proteins, lipids, and carbohydrates

13

THE CELL CYCLE

•S

synthesizes DNA

14

THE CELL CYCLE

•G2 –

finishes making proteins, membranes, gets ready to divide

15

THE CELL CYCLE


Cytokinesis

the rest of the cell divides

16

THE CELL CYCLE


Cytokinesis

the rest of the cell divides

17

Phases of MITOSIS

- PROPHASE
- METAPHASE
- ANAPHASE
- TELOPHASE AND CYTOKINESIS

18

Apoptosis

regulated cell death

19

Meiosis

creates 4 non-identical haploid cells from 1 diploid cell

20

Meiosis:
Interphase

DNA is replicated
* During S phase!

21

Meiosis:
Meiosis I:

(Reductional division)
Homologous chromosomes separated

22

Meiosis:
Meiosis II:

(Equational division)
Sister chromatids separated

23

Mitosis
Prophase 1

•Crossing over
•Creates recombinant chromosomes

24

Mitosis
•Anaphase I:

•Separates homologouschromosomes•(Mitosis separates sister chromatids)