7
Run for your life
I Activities 7.1 to 7.7
Activity 7.1: Joints and the muscles that move them – a
check on understanding
Comparing hip and knee joints
Complete a copy of the table below, to compare movement at hip and knee joints, using the
information given in Figure 7.2, on page 100 in Edexcel Biology for A2.
Hip joint
Knee joint
type
articulating bones
additional bones
articulating surface(s)
permitted movement
Muscles for flexion and extension
Below is a diagram of part of a hind limb of a crouching quadruped, such as a rabbit or hare.
When the animal leaps which muscles (A, B, C, D or E) contract?
A
B
E
C
D
Sketch the bones and muscles when the limb is fully extended.
Activity 7.2: Muscle contraction simulation
See how a muscle fibre contracts in the animation available at:
www.sci.sdsu.edu/movies/actin_myosin.html
Edexcel Biology for A2 Dynamic Learning
© Hodder Education 2009
2
RUN FOR YOUR LIFE: ACTIVITIES 7.1 TO 7.7
Activity 7.3: Analysing states of contraction in skeletal
muscle fibres
Muscles are involved in maintaining body posture, in delicate movements, and in vigorous
actions too, at different times. Consequently, nervous control of muscle contraction may cause
relaxed muscle to contract slightly, moderately or fully, on occasions. In these different states of
contraction, the overall lengths of the sarcomeres are changed accordingly. These relative
changes are illustrated diagrammatically below, in a single sarcomere. Beneath the diagrams, is a
representation of part of a myofibril, seen at a particular stage of contraction. This representation
is not diagrammatic, but is based on an interpretation of a TEM. (See the TEM in Figure 7.6, on
page 104 in Edexcel Biology for A2, for example.)
1 a relaxed sarcomere
2 slightly contracted
sarcomere
thin filament
(actin)
thick filament
(myosin)
3 moderately contracted
sarcomere
Z-line
4 fully contracted
sarcomere
sketch representing a myofibril at a particular stage in contraction,
based on interpretation of a TEM of a sample of striated muscle
1 Identify the approximate state of contraction illustrated in the sketch of a TEM of a myofibril, shown above.
2 Sketch a similar myofibril, fully contracted. Label your drawing (sarcomere, Z band, light band and dark band).
Activity 7.4: Walking simulation
Try out the animation of human locomotion at:
www.bml.psy.ruhr-uni-bochum.de/Demos/BMLwalker.html
Can you recognise the moods and natures of friends and colleagues from the variety of gaits?
Edexcel Biology for A2 Dynamic Learning
© Hodder Education 2009
3
RUN FOR YOUR LIFE: ACTIVITIES 7.1 TO 7.7
Activity 7.5: Test yourself on muscle fibres – structure and
physiology
Contrast fast-twitch and slow-twitch muscle fibres by completing a copy of the table below.
Fast-twitch fibres
Slow-twitch fibres
numbers of mitochondria
amount of myoglobin
glycogen content
sarcoplasmic reticulum
capillary supply
potential to fatigue
how ATP is generated
likelihood of an oxygen debt arising
type of activity likely to be best suited for
Activity 7.6: Understanding ATP, structure and importance
1 By means of a labelled diagram, explain the structural connections between ATP, ADP and
AMP.
2 List six important features of ATP.
Activity 7.7: Mitochondrial structure in relation to
functions – an enquiry
The locations of the stages of cellular respiration in the eukaryotic cell are summarised in the
diagram below. Once pyruvate has been formed from glucose in the cytosol, the remainder of the
pathway of aerobic cell respiration is located in the mitochondria. Examine the diagram, and
then complete a copy of the table below concerning the relationship between structure and
function in the mitochondrion.
cytoplasm
ATP
enzymes of pyruvate breakdown
in matrix of mitochondrion
enzymes of glycolysis
in the cytosol
CO2
glucose
pyruvate
breakdown
pyruvate
reduced
hydrogen
acceptor
ATP
ADP
+ Pi
H 2O
glycolysis
hydrogen
acceptors
pyruvate
ATP
ADP
+ Pi
reduced
hydrogen
acceptors
mitochondrion
outer membrane
inner membrane
cristae
movement by
facilitated diffusion
sites of oxidation of
hyrogen acceptor
(water formation)
and ATP synthesis
O2
CO2
Structure in mitochondrion
Function or role
external double membrane
matrix
inner membrane
inter-membrane space
Edexcel Biology for A2 Dynamic Learning
© Hodder Education 2009