Lecture 20 (11b) - Cell Communication Part 2 Flashcards Preview

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Flashcards in Lecture 20 (11b) - Cell Communication Part 2 Deck (66)
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1

Record jumps

Frog - Rosie (6.5m)
Human - Jackie Joyner Kersee (7.m)

2

three types of vertebrate muscle

• skeletal
• cardiac
• smooth

3

Skeletal muscle

• voluntary movement, breathing, maintaining posture
• appear striped bc of regular arrangement of sarcomeres

4

Cardiac muscle

• beating of heart
• cells interdigitate, forming a mesh

5

Smooth muscle

• involuntary, movement of internal organs
• do NO have stripes of regularly arranged actin and myosin

6

One muscle is composed of

hundreds of thousands of muscle cells (fibers) bundle together with connective tissue

7

One cell is called a

muscle fiber - large and multinucleate
• comes from the fusion of many myoblasts during development)

8

Each muscle cell (one fiber) consists of

several myofibrils

9

1 muscle fiber = 1 cell

actin + myosin -->
sarcomere -->
myofibril -->
muscle fiber + CT -->
1 muscle

10

Muscle cells need lots of

mitochondria to make ATP

11

Muscle cell membrane

sarcolema

12

Muscle cell cytoplasm

sarcoplasm

13

Each myofibril consists of repeating units called

sarcomeres

14

Each sarcomere is made of

overlapping actin and myosin filaments

15

1 sarcomere is from

Z line to Z line

16

I band

actin

17

A band

myosin with overlapping actin
• darker because myosin is thinner

18

H zone

only myosin

19

Each myofibril =

plenty of sarcomeres repeating horizontally

20

Each sarcomere is bound by

Z lines which anchor the actin

21

A band

in the middle of the sarcomere
• all the myosin filaments

22

H zone

non overlapping part of actin

23

I band

non overlapping part of myosin

24

H zone and I band

non overlapping part of actin and myosin

25

Titin

holds the myosin to the Z
• "bungee cord" = resistance to stretch in a relaxed muscle

26

Sliding filaments cause the muscle to contract

actin slides past myosin = contraction

27

When a muscle contracts

• sarcomeres shorten and band pattern changes
• non overlapping parts - H and I - diminish because there is more overlapping between actin and myosin filaments

28

2 main actors of the muscle contraction

myosin and actin

29

Myosin

2 polypeptide chains coiled together, ending in a globular head
• a myosin filament is made of many molecules in parallel with heads projecting sideways

30

Actin filament

actin monomers in a long twisted molecule