BIOSCI 107 Short Answers Flashcards
What are the 6 Levels of Structural Organisation?
Chemical, Cellular, Tissue, Organ, System, Organismal.
What are the 4 Tissue Types?
Epithelial, connective, muscle, nervous.
What is the Function of Epithelial Tissue?
Protection, filtration, secretion, absorption, excretion.
What is the Function of Connective Tissue?
Protects and supports, binds organs together, stores energy, transport (blood).
What is the Function of Muscle Tissue?
Movement.
What is the Function of Nervous Tissue?
Detects changes.
What are the General Features of Epithelial Tissue?
Arranged in continuous sheets as single or multiple layers, held together by cell junctions.
What is the General Structure of the Basement Membrane?
Two parts: Basal Lamina and Reticular Lamina.
What does the Basal Lamina contain?
Collagen, laminin, other proteoglycans and glycoproteins.
What does the Reticular Lamina contain?
Fibrous proteins like fibronectin and collagen.
What are the 3 Functions of the Basement Membrane?
Supports overlying epithelium, acts as a physical barrier, provides a surface for epithelial cells to migrate.
How is Epithelial Tissue Classified?
By arrangement and shape.
What are the 3 Categories of Arrangement for Epithelial Tissue?
Simple, stratified, pseudostratified.
What are the 4 Categories of Shape for Epithelial Tissue?
Squamous, cuboidal, columnar, transitional.
What is Simple Squamous Epithelial Tissue?
Thin/flat cells found in Bowman’s capsule, inside eye, alveoli, inside heart.
What is Simple Cuboidal Epithelial Tissue?
Cuboidal/hexagonal boxes found in pancreas ducts, kidney ducts, thyroid, lens surface.
What are the Characteristics of the Basement Membrane?
Permeable, between epithelial and connective tissue, provides substructure for injury, gets reconstructed during healing.
How do we determine if something is Single or Multicellular?
Structure of duct, structure of secretory area, relationship between the two.
What are the Specialised Subtypes of Simple Squamous Tissue?
Mesothelium lines pericardial, pleural, peritoneal cavities.
Endothelium lines inside of heart and blood vessel.
What are the Specialised Subtypes of Simple Cuboidal Tissue?
None.
What are the Specialised Subtypes of Simple Columnar Tissue?
Cilia or microvilli.
What are the 11 Body Systems?
Integumentary, muscular, skeletal, nervous, endocrine, lymphatic and immune, cardiovascular, respiratory, digestive, urinary, reproductive.
What are the Functions of Connective Tissue?
Binds, supports and strengthens other tissues, transport system, stored energy reserves.
How does Connective Tissue Compare to Epithelial Tissue?
Unlike Epithelia: Not found on body surfaces, can be highly vascular
Like Epithelia: Supplied by nerves.
What is Connective Tissue Comprised of?
Extracellular matrix + cells.
What are the main Components of ECM?
Ground substance, 3 protein fibres.
What is Ground Substance made of?
H2O, proteins and polysaccharides.
What are some examples of Glycosaminoglycans (GAGs)?
Sulphated: Dermatan sulphate, heparin sulphate, keratan sulphate, chondroitin sulphate.
Non-Sulphated: Hyaluronic acid
What does Hyaluronic Acid do?
Binds cells together, lubricates joints and maintains shape of eyeball.
What does Hyaluronidase do?
Makes ground substance more liquid so they can move more easily in it.
What does Chondroitin do?
Supports and provides adhesive features of cartilage, bone, skin and blood vessels.
What are the 3 Features of Collagen Fibres?
Very strong/flexible, varying features for different tissues, 25% of our body.
What are the 5 Features of Reticular Fibres?
Made of bundled collagen, made by fibroblasts, provide strength/support, form part of basement membrane and networks in vessels, thinner, branching, spreads through tissue.
What are the Features of Elastic Fibres?
Thinner than collagen fibres, fibrous network, more strength and stability given by fibrillin (elastin surrounded by this), stretches up to 150%, in skin, blood vessels and lung.
How is Marfan Syndrome Caused?
Mutation on chromosome 15 causes elastic fibre defect, fibrillin is structural scaffold for elastin, leads to tall/long limbed/weakened heart valves individuals.
What is the Function of Fibroblasts?
Secrete components of the matrix.
What is the Function of Adipocytes?
Store fat.
What are the 2 Types of Connective Tissue?
Embryonic and mature.
What is a Bone?
Organ composed of several connective tissue types, including bone tissue.
What is Osteon made of?
Lamellae, lacunae, canaliculi, central canal.
What is Spongy Bone?
Porous inner bone tissue underneath compact bone.
What is Cancellous Bone?
Compact bone.
What is the Difference between Osteoblasts and Osteoclasts?
Osteoblast - lays down material
Osteoclast - gathers up material
How does Muscle Tissue Contract?
Cells use energy from hydrolysis of ATP to generate force.
What are the 3 Types of Muscle?
Skeletal, Cardiac, Smooth.
What are Striations?
Myofibrils within cells - these fill the cytoplasm.
What are the 2 Types of Myofibril?
Thick filaments (myosin), thin filaments (actin).
How are Myofilaments Arranged?
In compartments (sarcomeres).
What are the 3 Variations of Connective Tissue in Muscles?
Epimysium, perimysium, endomysium.
What are Intercalated Discs?
Desmosomes and gap junctions.
What are the 2 Types of Nervous System?
Central nervous system (brain/spinal cord)
Peripheral nervous system (all nervous tissue outside CNS)
What are the 3 Functions of Nervous Tissue?
Maintain homeostasis, initiate voluntary movements, perception/behaviour/memory.
Which activities does the Nervous System carry out?
- Sensory (CNS)
- Integrative
- Motor (PNS)
How can we Describe Neurons?
Have a cell body where dendrites convey nerve impulses (actin potentials), where a longer, single axon conducts nerve impulses to another neuron or tissue.
What are the 4 Features of Multipolar Neurons?
Have 2+ dendrites and 1 axon, most common neurons in CNS, all motor neurons are in this class, some of the longest.
What are the 4 Features of Bipolar Neurons?
2 processes (1 dendrite, 1 axon), cell body between axon and dendrite, rare/small, special sense organs relay info from receptor to neurons.
What are the 5 Key Features of a Unipolar Neuron?
Dendrites and axon are continuous, cell body off to one side, whole thing from where dendrites converge called axon, most sensory nerves are unipolar, v.long - like motor nerves.
What is an Anaxonic Neuron?
Found in brain and special sense organs, function not understood.
What are the Functions of Neuroglia?
Physical structure, repair, phagocytosis, nutrient supply, regulate interstitial fluid.
Where can Neuroglia Divide?
In mature nervous systems.
What are the 4 Functions of an Astrocyte?
Support, neuron communication, maintain environment, maintain blood-brain barrier.
What is the Function of Ependymal Cells?
Produce cerebrospinal fluid to line CSF-filled ventricles and central canal of the spinal cord.
What is the function of a Schwann Cell?
Insulation and support for non-myelinated axons (myelin sheath).
What is the Function of a Satellite Cell?
Surround neuron cell bodies and support/fluid exchange.
What is Epimysium?
Outer layer of main muscle body.
What are the 4 Key Features of Smooth Muscle?
Can be packed in together, between dense bodies are intermediate filaments, lots of single nuclei, very open.
What is the Function of Neuroglia in the Brain?
Envelope capillaries to form blood-brain barrier.
What are the 4 Functions of a Plasma Membrane?
Physical barrier, mediate movement, cell-cell identification, intercellular communication.
What is the Phospholipid Bilayer made of?
Transmembrane proteins, peripheral membrane proteins, glycoproteins.
What are the 6 Functions of Membrane Proteins?
Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and ECM.
What is the Primary Function of a Nucleus?
To house/protect DNA in eukaryotic cells.
What are the Secondary Functions of a Nucleus?
rRNA and ribosome production, compartmentalisation, segregating molecules, temporal/spatial control of cell function.
What are the Stabilising Bonds in DNA?
Phosphodiester bonds, hydrogen bonds.
What are the Components of a Functional Ribosome?
Large subunit + small subunit.
What are the 2 Locations of Ribosomes in a Cell?
Free in the cytoplasm or attached to the rough ER.
What is the Endoplasmic Reticulum?
Extensive network of tubes and tubules, stretching out from the nuclear membrane.
What is the Difference in Purpose of Smooth and Rough ER?
Rough - Sorting and packaging
Smooth - Production of lipids/carbs, housing unit for tissue specific proteins.
What is the Golgi Complex?
Complex of flattened membranous sacs cisternae, stacked on top of one another, curved into a cup shape.
What are the 4 Functions of Lysosomes?
Digestion: substances that enter a cell, cell components, entire cells, any extracellular digestion.
What are the 3 Components of Mitochondria?
Outer mitochondrial membrane, inner mitochondrial membrane (folds called cristae), fluid filled interior cavity called the mitochondrial matrix.
What are the 3 Functions of the Cytoplasm?
Maintain size, shape and integrity, acts as scaffolding across cell, intracellular transportation and cell movement.
What are the 3 Main Fibres?
Microfilaments, intermediate filaments, microtubules.
What are the 4 Features of Microvilli?
Comprised of actin molecules, found around the periphery, bear tension and weight by anchoring cytoskeleton, assembled and disassembled.
What is the Main Function of Proteins?
Carrying out cellular functions.
Why is Gene Expression Important?
Housekeeping proteins are actively transcribed from DNA continuously, signalling proteins are produced in response to stimuli.
What Factor Initiates Transcription in Eukaryotes?
Proteins called basal transcription factors.
What is the Adaptor Molecule for mRNA Triplet Specification?
Transfer RNA (tRNA).
What is the Role of tRNA?
Enzymes called aminoacyl tRNA synthestases ‘charge’ the tRNA by catalysing the addition of amino acids to tRNAs (requires ATP).
What is the Mechanism of Translation?
Ribosome subunits are assembled in the nucleolus and transported to the cytosol.
What are Amino Acids?
‘Building blocks’ that form proteins (20 used in protein construction).
What are the 2 Functional Groups associated with Amino Acids?
Carboxyl group, amino group.
Which 3 Factors Determine the Properties of a Protein?
Size, content of amino acids, sequence of amino acids.
How does a Peptide Bond join Amino Acids Together?
- Side chains ‘stick out’ from backbone
- Directional ‘N-terminus’ and ‘C-terminus’
- It is flexible
How do we Differentiate between a Peptide and a Protein?
<50 amino acids = Peptide
>50 amino acids = Protein
What is Interphase made up of?
G1 phase, S phase, G2 phase.
What happens during the Mitotic Phase?
PPMAT: Prophase, prometaphase, metaphase, anaphase, telophase.
Where are the 3 Major Checkpoints of the Cell Cycle?
G1 to S, G2 to M, M (SAC).
How are Secondary Structures Formed?
O from C=O forms hydrogen bond with H from N=H, shape adopts two common structures (alpha helix or beta sheet).
What will Alteration in the Amino Acid Sequence do?
- Alter target enzyme can bind
2. And how efficiently it can degrade
How is Energy Stored from Cellular Respiration?
Transferred from other complex molecules to ATP, energy ready to be used again.
How is Energy Used from Cellular Respiration?
Transferred from ATP to complex molecules, molecules can be formed or used to do work.
What are the 3 Categories of Food and what are they Broken Down into?
Proteins: amino acids
Fats: simple fats
Carbohydrates: simple sugars (absorbed)
What are the 3 Major Biochemical Pathways?
Glycolysis, Krebs Cycle, Electron Transport Chain
What are the Ratios of Glycolysis in terms of ATP?
Two ATP are required, and four ATP are produced. Net gain of two ATP.
How is Acetyl CoA Formed?
- Either conversion of Pyruvic acid to acetyl CoA anaerobic process in mitochondrial matrix.
- Or carbs can be metabolised then converted to acetyl CoA.
What is the Function of the ETC?
Generates energy, exploited to make ATP.
What is the brief Process of ETC?
ETC uses energy from redox reactions to fuel pumping of protons up a concentration gradient from matrix to inner membrane space.
What happens when Insulin is Absent?
No glucose in cells, no cellular respiration, no ATP from glucose, no glycogen ‘for a rainy day’.
What is the Function of Insulin?
Promote glucose uptake into cells.
What is the Function of Glucagon?
Stimulates breakdown of glycogen to increase blood sugar levels.
What are the 4 Steps of Intercellular Signalling?
Signal reception, signal processing, signal response, signal deactivation.
What Impacts do Steroid Hormones have?
Direct effect, bind to a receptor protein, hormone-receptor complex transported to nucleus, alters gene expression.
What are the 2 Types of Receptor?
Cytosolic/nuclear or membrane-bound/cell surface receptors.
What are G Proteins?
Intracellular peripheral membrane proteins closely associated with transmembrane signal receptors.
What happens during Reception?
The receptor activates an enzyme.
What happens during Signal Transduction?
The enzyme activates a relay molecule or 2nd messenger; the 2nd messenger activates a signal transduction pathway (usually a phosphorylation).
What is Signal Transduction?
Converts an easily transmitted extracellular message into a greatly amplified intracellular message that carries into throughout the cell and induces a cell response.
What does the Sperm need to Penetrate to Fertilise an Egg?
The zona pellucida.
When does Compaction occur?
After the 8 cell stage.
What are the 3 Models for Cell Differentiation?
Mosaic (not accepted), positional, polarity.
What is the Positional Model?
Cells differentiate into ICM or trophoblast depending on their contact with the external environment.
What is the Polarity Model?
Polarised cells can divide in 2 ways.
What does the Polarity Model say will happen if Cell Division is Parallel to the Polarisation Axis?
The 2 daughter cells will be polarised and remain on the outside of the cell.
What does the Polarity Model say will happen if Cell Division is Orthogonal to the Polarisation Axis?
1 daughter cell will be polar and 1 will be apolar.
What happens to the Blastocyst on Day 4/5 of Development?
Fluid moves through the trophoblast into the centre of the morula and forms the blastocyst cavity.
Where are Human Foetus Tissues Derived from?
Epiblast.
Where are Extra-Embryonic Support Structures Derived from?
Hypoblast and epiblast.
What are the 3 Germ Layers?
Ectoderm, mesoderm, endoderm.
What is Embryonic Folding?
Elongated oval-disc embryo transforms into a 3D structure.
What is Longitudinal Bending?
Flat disc of the trilaminar embryo bends along the rostro-caudal axis, creating a C-shape.
What is Transverse Folding?
Folding along the transverse axis of the embryo.
Where does Chordamesoderm Form?
As a rod-like structure along the midline of the embryo.
Where does Paraxial/Somitic Mesoderm Form?
At both sides of the midline.
Where does Intermediate Mesoderm Form?
As paired cylindrical structures lateral to the paraxial mesoderm.
Where does Lateral Plate Mesoderm Form?
As flattened sheets lateral to the intermediate mesoderm.
What is Unique about Chordamesoderm?
Only non-paired mesodermal structure.
How is the Notochord Formed?
16 days after fertilisation, cells migrating through the rostral tip of the primitive streak will position themselves at the midline, forming the notochord.
What does the Intermediate Mesoderm give rise to?
The urogenital system.
Which 2 Sheets does the Lateral Plate Mesoderm Form?
Visceral and Parietal later plate mesoderms.
What is the Functional Significance of the Pharyngeal Arches?
Each arch is a developmental unit with develops into a specific head or neck structure, also associated with specific blood vessels, muscles and nerves.
What is the Function of the Placenta?
To provide oxygen and nutrients to the fetus, whilst removing carbon dioxide and other waste products.
What is the Role of Trophoblasts during Implantation?
Forms the walls around the blastocyst cavity and differentiates into 2 tissues: cellular trophoblast and syncytial trophoblast.
What is the Function of the Amniotic Sac?
Storage for metabolic residues and a protective structure - shock absorption.
What is the Function of the Yolk Sac?
Delivers nutrients through vitelline circuit.
How is the Allantois Different in Mammals and Birds?
Vestigial in humans, large and highly vasculised in birds.
What is the Embryonic Origin and Position of the Amniotic Sac?
Cavity within the epiblast,
What is the Embryonic Origin and Position of the Yolk Sac?
Cells of hypoblast migrate to cover inner walls of blastocyst cavity, forms gut
What is the Embryonic Origin and Position of the Allantois
Cloacal membrane, forms umbilical cord.
