BTEC Applied Science Unit 1 Biology

Describe the function of the tonoplasts

Membrane the surrounds the vacuole. Protects the vacuole, isolates it from harmful substances and controls water flow in and out of the vacuole

Describe the adaptations found in a palisade cell

Closely packed together
Chloroplasts
Large vacuole

Explain why palisade cells are closely packed together

To form a continuous layer in the leaf

Describe the adaptations of a root hair cell

Root hair shape
Large vacuole
Thin cellulose walls

Explain why root hair cells have thin cellulose walls

Encourage movement of water and minerals into the cell. Short distance for osmosis and diffusion

Describe the adaptations of a sperm cell

Lots of mitochondria
Shaped head containing acrosome (with enzymes)
Haploid nucleus
Tail for movement

Explain why sperm cells contain acrosome in the head

To digest the zona pellucida to allow entry into the egg cell

Explain why sperm cells have a haploid nucleus

Contains half the genetic material.

Describe the adaptations of egg cells

Contains a haploid nucleus
Protective outer layer (zona pellucida)
Corona radiata

Explain why egg cells have a haploid nucleus

Contains half the genetic material

Explain why egg cells have a zona pellucida (protective layer)

Protects the cell and only allows one sperm cell to enter.

Explain why egg cells have a corona radiata (two or three layers attached to the zona pellucida)

Contains all of the proteins needed to develop the fertilised cell

Describe the adaptations of red blood cells

No nucleus (mammals only)
Biconcave shape
Haemoglobin
Flexible

Explain why red blood cells don't contain a nucleus

Allows for more oxygen to be carried in the cell

Explain why red blood cells have a biconcave shape

Increased surface area for gas exchange

Describe the function of the nucleolus

Produces ribosomes and RNA

Describe the function of the cell wall

Provides rigidity and protection to the cell

Describe the function of the chloroplasts

Site of photosynthesis as they contain chlorophyll

Describe the function of the plasmodesmata

A channel through the cell wall the allows transport of materials from one cell to another

Describe the function of the amyoplasts

Stores starch and converts starch back into glucose when the plant needs energy

Describe the function of the vacuole

Stores water and chemicals for cell use. Also maintains turgor of cell

Why are gram positive bacteria more susceptible to antibiotics?

Permeable cell wall whereas gram negative bacteria has a semi-permeable cell wall

Explain why the palisade cell has a large amount of chloroplasts

To absorb lots of light for photosynthesis

Explain why palisade cells have a large vacuole

To maintain turgor (pushes against the cell wall to maintain rigid shape)

Explain why root hair cells have an elongated section known as the root hair

Increased surface area for maximum movement of water into the cell

Explain why root hair cells have a large vacuole

Contains cell sap with low water potential to encourage water into the cell

Explain why a sperm cell has an undulipodium (tail)

To allow the sperm to move to the egg

Explain why sperm cells contain large numbers of mitochondria

To produce the large amounts of energy needed for movement

Explain why sperm cells have a shaped head

To push through the protective layer of the egg cell

Explain why red blood cells contain haemoglobin

To bind with the oxygen in order for it to be carried around the body

Explain why red blood cells are flexible

To fit through the tiny blood vessels such as capillaries

Describe the adaptations of white blood cells

Multi-lobed nucleus
Enzymes found within the lysosomes

Explain why white blood cells have a multi-lobed nucleus

To enable the cell to squeeze through tiny gaps when travelling to the site of infection

Explain why the lysosomes found within the cytoplasm of white blood cells contain enzymes

To digest engulfed pathogens

Name the 3 different types of epithelial tissue

Squamous epithelial tissue
Columnar epithelial tissue
Endothelium tissue

Describe squamous epithelial tissue

A lining tissue that is only one cell thick. Made from squamous cells that form a smooth, flat layer.

Where can squamous epithelial tissue be found?

As it is a lining tissue it can be found inside alveoli

How can squamous epithelial tissue be damaged by smoking?

Inflammation and scarring of tissue
Tissue gets thicker and produces more mucus
Diffusion pathway is increased

What does COPD stand for?

Chronic Obstructive Pulmonary Disorder

What symptoms can be displayed from COPD?

Breathlessness
Persistent coughing
Phlegm build up

What conditions are considered part of COPD?

Emphysema
Bronchitis
Asthma

Describe columnar epithelial tissue

Column shaped ciliated cells and goblet cells held in place by a membrane

What is meant by the term ciliated cell?

A cell covered in cilia. Cilia are fine, hair like projections that 'sweep' away pathogens from the lungs

How does smoking affect ciliated columnar tissue?

The cilia can break, lessening the 'sweeping action' overall. This leads to a build-up of mucus.

What is the role of the goblet cell?

To produce mucus

How do goblet cells and ciliated cells work together?

Goblet cells produce mucus that sticks to pathogens, whilst cilia 'sweep' away the mucus containing the pathogens

How does smoking affect the alveoli?

Reduces the elasticity so pockets of air form that cannot be expelled

Where is endothelial tissue found?

Lining the inside of blood vessels, lymphatic vessels and the heart

Describe the structure of endothelial tissue

A layer of flattened cells, one layer thick

What is atherosclerosis?

The process of white blood cells encouraging the deposition of fatty substances (cholesterol) below the endothelial lining

What factors can increase the likelihood of atherosclerosis?

Smoking
High blood pressure

What conditions can atherosclerosis cause?

Angina
TIA (mini strokes)
Heart attack
Aneurysm and haemorrhage

Name the three types of muscle tissue

Skeletal
Cardiac
Smooth

What type of control is exhibited in skeletal muscle?

Voluntary control

What type of control is exhibited in cardiac muscle?

Involuntary control

What type of control is exhibited in smooth muscle?

Involuntary control

Where can skeletal muscle be found?

Attached to bones

Where can cardiac muscle be found?

In the heart

Where can smooth muscle be found?

In the walls of hollow organs such as the stomach and bladder

Put the following in order of size from largest to smallest: fibre, muscle, filaments, myofibril, bundle of fibres

Muscle, bundle of fibres, fibre, myofibril, filaments

Muscle fibres are many cells joined together. What organelles do these cells share?

Nuclei and cytoplasm, inside which are many mitochondria and specialised ER

Why do muscle cells contain many mitochondria?

To provide large amounts of energy to the muscle for contractions

Give the term used to describe the stripy bands seen within skeletal muscle under a microscope

Striations

Myofibril is made up of dark and light bands. What are the names given to these dark and light bands?

Dark band = A-band
Light band = I-band

Which line is present in the middle of the A-band?

M line

Which line is present in the middle of the I-band?

Z line

What is the name given to the space between two Z-lines?

Sarcomere

Myofibril is made up of alternating thick and thin filaments. What are the names of these filaments?

Thick = myosin filament
Thin = actin filament

What happens to the sarcomere during muscle contraction?

It shortens

What are the two types of skeletal muscle?

Fast twitch and slow twitch

Which sports are slow twitch muscle fibres best for?

Long distance running and cycling

Fast twitch muscles can be further divided into two sub-categories, what are they?

Fast twitch oxidative muscles and fast twitch glycolytic muscles

Which sports are fast twitch oxidative muscle fibres best for?

Mid-range sports such as1500m

Which sports are fast twitch glycolytic muscle fibres best for?

Sprinting, short burst sports

What type of exercise are slow twitch muscles designed for?

Aerobic exercise

What type of exercise are fast twitch muscles designed for?

Anaerobic exercise

In which type of muscle fibre is the speed of contraction slowest?

Slow twitch

In which type of muscle fibre is the speed of contraction highest?

Fast glycolytic twitch

Describe the characteristics of slow twitch muscle fibres

Less sarcoplasmic reticulum (specialised ER)
More mitochondria
More myoglobin
A dense capillary network

Describe the characteristics of fast oxidative muscle fibres

Similar to slow twitch with many mitochondria, myoglobin and capillaries
Hydrolyse ATP faster to contract more quickly

Describe the characteristics of fast glycolytic twitch muscle fibres

Few mitochondria and capillaries
Less myoglobin
Large concentration of glycogen for anaerobic respiration

What structures make up the nervous system?

Brain, spinal cord, nerves

What is the scientific name for nerve cells?

Neurones

Name the organelles of the neurone

Dendrite, cytoplasm, nucleus, soma, axon, myelin sheath, axon terminal, Schwann cell, node of Ranvier

What parts of the nervous system make up the central nervous system?

Brain and spinal cord

Which parts of the nervous system make up the peripheral nervous system?

Neurones

Define the term 'synapse'

The small gap in between the axon terminal of one neurone and the dendrite of the next neurone

Define the term 'action potential

The impulse passed along the axon

Define the term 'resting potential

When the neurone is not transmitting an action potential. During this time the K+/Na+ pump is at work

What are the 5 sensory receptors?

Touch, taste, smell, hearing, sight

Describe the myelin sheath

A thick insulating layer around the axon

Describe the dendrites

Highly branched fibres that conduct impulses

Describe the axon

A long single fibre that carries nerve impulses

Describe the Schwann Cell

A cell wrapped around the axon, forming the myelin sheath

Describe the nodes of Ranvier

Gap in the myelin sheath where the axon is exposed

Describe the differences between myelinated and non-myelinated cells

Myelinated cells are longer and can transmit impulses faster down the axon

Why do myelinated neurones transmit action potentials quicker than non-myelinated

Insulated by myelin sheath
Impulse 'jumps' from node to node (where the sodium gates are located)

What is the potential difference across the axon membrane during resting potential?

-70mV

What is the potential difference across the axon membrane during an action potential?

+35mV

What charge does the inside of an neurone have when it is polarised?

Negative