Forensic biology Flashcards by Alex Howe

What components are in the plasma membrane and what is its function?

Phospholipid bilayer
Fluid mosaic model
Movement in and out
Cell signalling

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What is the function of the cytoskeleton?

Provide shape and movement

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What do Actin Microfilaments do? Where are they found?

Inner edge of cytoskeleton
Resist tension

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What do Microtubules do? Where are they found?

Interior of the cytoskeleton
Resist compression

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What do Intermediate filaments do? Where are they found?

Hold organelles in place
Cytoskeleton

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What is the cytoplasam?

Fluid inside of the cell
contains proteins, salts and maintains the internal environment

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What are the units of Ribosomes?

S=svedberg

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What ribosome unit is Eukaryotic?

80s, joint 40s and 60s

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What ribosome unit is Prokaryotic?

70s, joint 50s and 30s

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What are Svedberg units used for?

Used to measure the sedimentation rate of particles during centrifugation
Larger sediments faster

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What are some main features of prokaryotic cells?

Lack a membrane-enclosed nucleus
Simple and small = 0.1-5um
Unicellular

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What are the structures in a prokaryotic cell?

Cytoplasm
ribosomes
nucleoid
plasmids
cell wall
slime capsule
flagella
pilli

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What is the function of the cell wall?

Protection and structural support
Only allow certain molecules to pass

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What is the function of the slime capsule?

Protection from chemical attacks
adhesive
immune system protection

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What is the function of flagella?

Movement

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What is the function of Pilli?

Adhesive to epithelial surfaces
Conjugation of genetic material
Uptake of proteins and DNA
motility

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What are the main features of Eukaryotic cells?

Complex and large 10-100um
Multicellular
Compartmentalisation

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What are the organelles found in Eukaryotic cells?

Ribosomes
Cytoplasm
nucleus
mitochondria
centrioles
rough endoplasmic reticulum
smooth endoplasmic reticulum
golgi apparatus
vesicles/lysosomes

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What is the function of the mitochondria?

Converts chemical energy to ATP
cristae

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What is the function of centrioles?

Involved in cell replication (mitosis& meiosis)
Organise microtubules that attach to chromosomes
spindle lengthens -> shortens

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What organelles are involved in the secretary pathway?

Both endoplasmic reticulums
golgi
vesicles

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What is the function of Rough endoplasmic reticulum?

Ribosomes on the outside
Synthesise and sort proteins
sends to the smooth

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What is the function of Smooth endoplasmic reticulum?

No ribosomes = no synthesis
Metabolic processes

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What is the function of the Golgi appartus?

Processes proteins
Packaging

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What is the function of vesicles?

Membrane-bound protein ready for delivery

What are lysosomes?

Vesicles containing digestive enzymes

What are the components in the plasma membrane?

Phospholipid bilayer Hydrophilic tails Hydrophobic heads Receptor proteins Channel proteins Carrier proteins

What is ATP?

Releases energy from glucose It is adenosine triphosphate

Where do Specialised cells come from?

Pluripotent stem cells

What are Squamous, Columnar , Cuboidal and Ciliated cells all associated with?

Epithelium (Skin)

What are the 3 main layers to epithelial tissue? In order

1. Epidermis 2. Dermis 3. Subcutaneous

Describe the Epidermis function

Protection Contains melanin Helps prevent dehydration

Describe the Dermis function

Filled with collagen proteins Hair follicles Sweat glands Blood and lymph vessels Nerves

Describe the Subcutaneous

Contains collagen networks Adipose tissue (body fat)

What is the role of the Sebaceous gland found in the dermis?

Provides 90% of surface lipids Sweat glands help thermoregulation

What are the different types of skin injuries?

Enter the body: Cuts, lacerations, gashes and tears Surface wounds: Scrapes, abrasions, scratches and floor burns Bruises: crushing with bleeding under the skin

What are the 4 main muscle structures? In order of size

1. Skeletal Muscle 2. Muscle cell 3. Myofibril 4. Sarcomeres

Describe muscle relaxation

Sarcomeres protein filaments actin and myosin are blocked by troponin and tropomyosin

Describe muscle contraction

Ca+ present ATP-bound myosin head binds to actin and pulls creating a contraction

How do muscles relax after contraction?

ATP binds to myosin head to stop the binding

What is the blood composition?

55% Plasma <1% leukocytes & Platelets 45% Erytheocytes

What protein is secreted to promote erythrocytes being produced?

Erythropoietin

What are the main specialised components to Erythrocytes?

Haemoglobin - binds to O2, Protoporphyrin IX and Ferrous Ion Mature = no nucleus or organelles Small and flexible = movement Biconcave shape = Maximum surface area for absorption

What are the main types of leukocytes?

Granulocytes - Basophil, Eosinophil and Neutrophil Lymphocytes Monocytes

What are the main specialised components of Thrombocytes (platelets)?

Aggregate at sites of vascular and blood injury less than 10 day lifespan Blood clotting

What is the Artery composition?

Tunica Adventitia - Outer layer contains fibroblasts Tunica Media - Middle layer containing smooth muscles - has lots of this Basement membrane - Inner layer Tunica intima - Most inner layer containing endothelial cells Small lumen = high pressure

What is the Vein composition?

Tunica Adventitia - Outer layer contains fibroblasts Tunica Media - Middle layer containing smooth muscles - has less of this Basement membrane - Inner layer Tunica intima - Most inner layer containing endothelial cells Wide lumen = low pressure Valves = Prevent flow back

What is the Integument System?

Body surfaces First layer of defence

What are the functions of the Integument System?

Protection from dehydration, Injury, Pathogens Regulate body temperature Sensory interface for the environment

How does the Integument system interact with the Immune system?

Physical barrier from infection

How does the Integument system interact with the digestive system, Endocrine & skeletal?

Synthesises vitamin D Required to absorb calcium

How does the Integument system interact with the Cardiovascular system?

Conserve or release heat by constricting or dilating blood vessels

How does the Integument system interact with the Nervous system?

Transmit sensations

How does the Integument system interact with the Respiratory system?

Cilia in respiratory tract

How does the Integument system interact with the Urinary system?

Excretes waste product

What is Algor mortis and when does it happen?

Cooling of the body Less than 15 min

What is Rigor mortis and when does it happen?

Contraction of the muscle More than 15 min

What is Livor mortis and when does it happen?

Blood pooling Past 20min fixes below 12 hours

How is Livor mortis used to identify if a body has been moved?

Blood pools in the lowest part of the body Leaves red-blue-purple discoloration

What are the stages of decomposition?

1. Fresh (Autolysis) 2. Bloat 3. Active Decay (Putrefaction) 4. Advanced decay 5. Skeletisation

What happens in the Bloat stage of Decomposition?

Cells break down through hydrolytic enzymes and bacteria Green colouration on the abdomen Anaerobic bacteria produce gases and skin becomes marbled

What happens in the Active Decay stage of Decomposition?

Fluids purge

What factors affect decomposition?

Temperature Oxygen availability Humidity Cause of Death Body Size/Weight Clothing

What is the function of the Small Intestine?

Absorb nutrients Enzymatic digestion Moves food along GI tract

What is the function of the Large Intestine?

Absorbs water and electrolytes Forms and propelling faeces Produce and absorb vitamins (K&B)

Forensic biology Flashcards

(66 cards)