Support and movement

Question 1

What structure features of plants help support them?

Answer 1

Turgor pressure
Shoot and root systems
Pith/ cortex relationship
Vascular bundles

Question 2

What is the pith made up of?

Answer 2

Parenchyma
Thin cell walls
Able to expand in response to increasing fluid in vacuole
Can exert pressure on tissue around them

Question 3

What is the cortex made up of?

Answer 3

Collenchyma
Have primary wall with some thickening
Provides support and offers flexibility for plant to move in the wind

Question 4

Why are vascular bundles surrounded by sclerenchyma?

Answer 4

Sclerenchyma have a thick secondary cell wall so they can bend and recoil (elasticity)
Allows plant to stretch and bend

Question 5

What is the purpose of lateral roots?

Answer 5

Primarily absorption of water and dissolved minerals

And some support provided

Question 6

What is the purpose of the primary root/ tap root?

Answer 6

Anchorage and stability

Question 7

What are three types of skeletal systems used by animals?

Answer 7

Hydrostatic skeleton
Exoskeleton
Endoskeleton

Question 8

Describe a hydrostatic skeleton.

Answer 8

Capsule of fluid surrounded by two layers of muscle: circular and longitudinal
Fluid filled cavity acts as a rigid column on which muscles act

Question 9

What is an example of an organism with a hydrostatic skeleton?

Answer 9

Earthworm

Question 10

How does a hydrostatic skeleton help an animal to move?

Answer 10

Circular muscles contract: elongating and narrowing the body
Longitudinal muscles contract: shorten and thicken the body
Segmental contraction of muscles and anchorage by bristles drives the body forwards: burrowing

Question 11

What are some organisms that use an exoskeleton?

Answer 11

Mollusks: clams and mussels
Arthropods: insects and crabs

Question 12

Describe an exoskeleton.

Answer 12

Hard outer surface that provides protection of soft tissues like armour
Made of chitin arranged in many layers

Question 13

What are some benefits of an exoskeleton made of chitin?

Answer 13

Strong and light
Can be mineralised to become harder
Thin and flexible at joints

Question 14

What are some issues with the use of an exoskeleton?

Answer 14

Can be crushed
Does not grow in line with body: must molt the exoskeleton (ecdysis)
Potential vulnerability until it hardens

Question 15

What are the two types of endoskeleton?

Answer 15

Cartilaginous

Bony

Question 16

Why can’t ants get reallyyyy big?

Answer 16

It would need to develop a significantly stronger and thicker skeleton to support an increased mass, if the exoskeleton became thicker and stronger it would be too heavy for the ant to move with
Sad times, ant must stay as small boi

Question 17

What is the benefit of an endoskeleton made of cartilage?

Answer 17

Buoyant
Efficient
Flexible

Question 18

Issues with an endoskeleton made of cartilage?

Answer 18

Cartilage is avascular so the skeleton must remain thin to allow diffusion of nutrients from surrounding tissues
These thin skeletons can’t support the fish outside of water
Sad times, fishy must stay as wet boi

Question 19

What are the benefits of a bony endoskeleton?

Answer 19

Rigid support against gravity
Supports weight of large animals on land
Dynamic: responds to physiological loading

Question 20

What does a bony endoskeleton develop from?

Answer 20

A cartilaginous skeleton

Question 21

What is in the central cavity of bones?

Answer 21

Yellow marrow

Question 22

What is the benefit of bones not being solid?

Answer 22

Reduces weight

Strength: helps resist compression and tension

Question 23

Is skeletal muscle striated or non-striated?

Answer 23

Striated

Question 24

Is skeletal muscle voluntary or involuntary?

Answer 24

Voluntary

Question 25

Three primary functions of skeletal muscle?

Answer 25

Movement
Posture
Heat production

Question 26

What is a muscle belly?

Answer 26

Central fleshy part of a muscle

Question 27

What are the two main components of a muscle?

Answer 27

Contractile cells

Connective tissues

Question 28

What is the functional unit of a muscle?

Answer 28

The muscle cell/ muscle fibre

Long multinucleate cells formed by a collection of microfibrils, which are formed from the myofilaments actin and myosin

Question 29

What is the benefit of fibres in muscles being arranged in parallel?

Answer 29

Wide range of movement

Question 30

What is the drawback of fibres in muscles being arranged in parallel?

Answer 30

Not particularly strong

Question 31

What is the benefit to muscle fibres being arranged at an angle?

Answer 31

Stronger force of contraction

Question 32

What is the drawback to muscle fibres being arranged at an angle?

Answer 32

Limited range of movement

Question 33

What is the function of tendons?

Answer 33

Transfer the force of a muscle to bone

Question 34

Describe the structure of tendons.

Answer 34

Made of mostly type 1 collagen
Two specialised regions: 
myotendinous junction (where tendon attached to muscle)
osteotendinous junction (where tendon attached to bone)

Question 35

What does isotonic contraction mean and what are the two types of isotonic contraction?

Answer 35

Constant tension: tension in the muscle causes changes in the length of the muscle
Concentric and eccentric (Poh)

Question 36

What happens in a concentric muscle contraction?

Answer 36

Muscle gets shorter when it contracts

Question 37

What happens in an eccentric muscle contraction?

Answer 37

Muscle lengthens

Question 38

What is an isometric contraction?

Answer 38

Muscle stays roughly the same length during contraction