BIOL 101 Lab Practical #2

What are the four major categories of tissue?

epithelial, connective, muscle, and nervous

Where is epithelial tissue found?

covering the surface of the body and lining surfaces of organs and glands

What acts as the foundation and anchor for epithelium?

basement membrane

What are the types of epithelial tissue and what are their functions and locations?

simple squamous: transport materials; lining of blood vessels

stratified squamous: acts as protective layer for underlying tissues; lining of the mouth

simple cuboidal: secretion and absorption; sweat glands

stratified cuboidal: protection for ducts and surfaces; lining of sweat glands

simple columnar: secretion and absorption; intestinal lining

stratified columnar: protection, secretion, and absorption; lines inner eyelids

pseudo stratified columnar: secretion and absorption; lining of trachea

What are the main muscle types and what do they look like?

skeletal: long fibers, many nuclei and striations

cardiac: short fibers, single nucleus and striations

smooth: short and flat fibers, single nucleus and non-striated

Whats the main function of muscle tissue?

move the body or substances in the body

What are the functions and locations of the 3 muscle tissues?

skeletal: contract to produce the force to move our body; attached to skeleton

cardiac: contract to pump blood through heart and cardiovascular system; wall of heart

smooth: contract to manipulate hollow spaces in internal organs and produce movement of their contents; walls of soft organs (stomach, intestines, bladder, and blood vessels)

What is the only muscle type that uses voluntary contraction?

skeletal

What is the only muscle type that doesn’t contain sarcomeres?

smooth

How do cardiac cells connect to each other?

intercalated discs

What tissue type maintains contractions for a long period of time?

smooth muscle

What are the different connective tissues and what do they look like?

areolar: large protein fibers (collagen and elastin), also loosely arranged

adipose: a lot of extracellular matrix with nuclei throughout

dense: many collagen fibers

cartilage: single nuclei and extracellular matrix

bone: cylindrical structures with layers around them in hollow spaces

fluid: fluid matrix and formed elements (erythrocytes, leukocytes, and platelets)

What are the functions and locations of the different connective tissues?

areolar: support and binding of soft organs and tissues; surrounding soft tissues and organs

adipose: energy storage (as fat), cushioning, and insulation; beneath the skin, around internal organs

dense: connect and support tissues; tendons and ligaments

cartilage: support and protection of tissues and organs; connecting ribs to sternum and ends of long bones

bone: support and protection of the body and internal organs; compact bone

fluid: transport of nutrients and wastes throughout body, protection against infection, and prevention of blood loss when vessels are damaged; blood is found in blood vessels and heart

What are the different protein fibers in connective tissue?

collagen: larger, stronger, and more rigid

elastin: more flexible

What are the nuclei of cells that build up areolar connective tissue called?

fibroblasts

What are adipose connective tissue cells called?

adipocytes

Whats the structure of adipocytes?

mostly empty to allow storage room, and the nucleus and cytoplasm are often compressed to one corner or side

What does the high proportion of collagen fibers do in dense connective tissue?

make it stronger and more resistant to stretching stresses

What are the cells of cartilage connective tissue called?

chondrocytes

What is the matrix of cartilage called?

lacunae

What does the large amount of extracellular matrix do in cartilage?

makes it strong while limiting the blood supply to living cells, making damaged cartilage slow to heal or may not heal at all

What does bone connective tissue matrix contain?

mineral deposits (calcium, phosphorus, and potassium), proteins, and ground substance

What does bone marrow contain?

adipose tissue and stem cells that generate blood cells

How is bone different from cartilage regarding healing?

bone contains spaces for blood vessels which provide bone with the resources needed to heal when damaged

What are smaller layers in compact bone called?

lamellae

What are the cylindrical structures in compact bone called?

osteons

What does the central canal in compact bones do?

provides space for blood vessels and nerves to permeate the tissue

What are the cells embedded in compact bone called?

osteocytes

What are the hollow spaces of compact bone called?

lacunae

How are osteocytes connected to each other and the central canal?

small channels called canaliculi

What are the two types of fluid connective tissue and where do they travel?

blood: cardiovascular system

lymph: lymphatic vessels

What is lymph?

interstitial fluid that is collected from body tissues and returned to the cardiovascular system via vessels of the lymphatic system

What are the formed elements in blood functions?

red blood cells (erythrocytes): maximize the transport of oxygen for he body in blood stream, and also carry some carbon dioxide waste

white blood cells (leukocytes): involved in body’s immune response to infection and tissue damage

platelets: assist in forming blood clots when vessels walls are damaged

What are nervous tissue cells called?

neurons

What is the role of neurons?

responding to stimuli, integrating information and issuing commands, and motor function

Where is the nucleus found and what are the extensions called in a neuron?

nucleus is found in cell body and extensions are dendtrites that communicate to other neurons, axons generate new impulses

What are support cells in nervous tissue called?

neuroglia

What do motor neurons do and where are they found?

take signals from the brain or spinal cord and relay them to other tissues and organs, which generates a response; peripheral nervous system

What do motor neurons look like?

cell body with dendrites, neuroglia nucleus can be seen surrounding

What organisms use binary fission?

simple organism such as archea and bacteria

What occurs during binary fission?

the bacterium’s single circular chromosome is replicated with each copy moving to opposite sides of the cell, then proteins begin pinching the cell in the middle, a septum forms, and the cell splits into 2

What cells use mitosis?

more complex eukaryotic cells

What is the usage for mitosis in multicellular organisms?

growth and repair

What is meiosis used for?

to create gametes (sperm and eggs)

What makes meiosis special?

the cells produced are not identical, nor do they even have the same number of chromosomes as the original cell

What must a cell do before it divides?

organize and duplicate its DNA

How do cells organize DNA?

wind the DNA around special proteins (called histones) to form chromatin, the chromatin is then shaped into a chromosome

How many chromosomes do humans have?

46, 23 pairs

What are the various states of chromosomes?

unwound (not yet duplicated or condensed), condensed (DNA wrapped tightly around histones, cell is committed to dividing), duplicated (the cell is preparing for division)

What are the two sides of a chromosome called when duplicated?

sister chromatids (identical)

Where are the sister chromatids held together?

centromere

What happens to the centromere throughout mitosis?

centromere is holding sister chromatids together during interphase, but splits during mitosis allowing them to seperate

What do the checkpoints do in the cell cycle?

ensure that the cell has enough building material, that the DNA replicates correctly, and that the chromosomes are aligned correctly to divide

What does interphase contain in the cell cycle?

G1 (cell is running daily activities and gather materials for next steps), G1 checkpoint, S (cell replicates DNA), and G2 (cell makes final preparations to divide), G2 checkpoint

What are the four phases of mitosis?

prophase: chromosomes condense and become visible, nuclear envelope disappears, centrosomes move to opposite sides, spindle fibers form and attach to chromosomes

metaphase: chromosomes line up at equator and spindle fibers attach sister chromatids to opposite poles

anaphase: sister chromatids are pulled apart and towards opposite poles, the cell begins to elongate

telophase: chromosomes are on opposite poles, nuclear envelope forms around chromosomes, spindle fibers break down

What is cytokinesis?

when the cell splits into two

What is a gamete’s job?

fuse with another gamete to produce offspring

What makes new cells via mitosis diploid and meiosis haploid?

mitosis: only divided once, creating each cell to have two sets of chromosomes, making it diploid with 2 products and 2 sets of chromosomes

meiosis: uses two divisions, meiosis 1 is responsible for dividing homologous pairs (1 parental and 1 maternal), meiosis 2 then divides the replicated chromosomes, making it haploid with 4 products that have 1 set

What are the ways of increasing genetic diversity?

crossing over, independent assortment, and sexual reproduction

How does crossing over create genetic diversity?

it leads to chromosomes that have new combinations of alleles

What occurs during crossing over of chromosomes?

homologous chromosomes physically meet with each other, where they can exchange genetic information

Why is the crossing over of chromosomes not random?

it ensures that the chromosomes still have a copy of each gene after crossing over happens, if not it could end up with missing or extra copies of gene which could lead to serious health effects if survivable

How is independent assortment random?

when separating homologous pairs, nothing determines which chromosome moves left and which moves right, this makes many possible arrangements when seperating the pairs

How many possible arrangements exist when producing a human gamete?

approximately 529

What’s the purpose of DNA?

responsible for coding information on how our cells should look and behave

What are traits?

the physical representation of our internal compenents

How are traits determined?

genes

What are genes?

segments of DNA that encode instructions that tell the cell how to make a protein, these proteins then contribute to how we look, behave, and function

What are the two copies of genes called and do they have to be identical/equal?

alleles; no, some dominate over others

How are dominant and recessive alleles shown?

dominant: capital letters

recessive: lowercase letters

What are alleles that create a blended appearance called?

incomplete dominance (red and white alleles make flower pink)

What are alleles that both show equally called?

codominance (red and white are both shown on flower)

What is the unique pair of alleles an individual has for a gene called?

genotype

What are homozygous and heterozygous genotypes?

homozygous: same alleles

heterozygous: different alleles

What is the physical result of a genotype?

phenotype

What are the different identifications of a genotype?

homozygous dominant: same dominant alleles

homozygous recessive: same recessive alleles

heterozygous: one dominant allele and one recessive allele

What are the phenotypes of the genotypes if freckles are dominant to no freckles?

FF: freckles

Ff: freckles

ff: no freckles

What is a Punnett square?

chart that predicts the offspring’s possible genotypes and phenotypes, as well as their probabilities

How do Punnet squares work?

separate each parent’s alleles to represent their possible gametes so that when we cross it with the other parents gametes, each offspring receives one allele from each parent

If the parents have four offspring, will this cause every Punnet square outcome to be represented?

no

Are there always only two possible alleles for a trait?

no, sometimes heterozygotes show a third phenotype due to incomplete dominance or codominance

What are the possible blood types alleles?

Ia (A antigen)

Ib (B antigen)

i (no antigen)

Why are Ia and Ib blood types both shown as capital letters?

they are both dominant and they codominate each other when both present

When does incomplete dominance occur?

when neither allele can mask each other (neither are dominant)

What are pedigrees used for?

trace patterns of inheritance by looking at several generations of a family and can trace genetic disease while giving family history, which helps provide insight for future generations

Is the pattern of inheritance the same for all genetic conditions?

no, the mutated allele can be dominant or recessive; when found on the sex chromosome, the condition tends predominately effect one sex (usually male since both male and female have X)

What do circles represent on a pedigree?

females

What do squares represent on a pedigree?

males

What do solid shapes represent on a pedigree?

affected individuals

What do white shapes represent on a pedigree?

unaffected individuals

What are the four possible mutations that can occur during crossing over?

deletion- loss of segment

duplication- extra segment

inversion- segment flipped

translocation- segment moves to different chromosome