GenBio Lecture 2

Genome

Collection of the genetic information

Gene

Basic unit of genetic information; determines the inherited characteristics

Chromosomes

storage unit of genes

DNA

a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life.

Ribonucleic acid

RNA stands for:

Deoxyribonucleic acid

DNA stands for:

A sperm fertilizes an egg → zygote undergoes rapid cell division called cleavage → cleavage leads to formation of blastula → blastula undergoes gastrulation

Enumerate the step by step reproduction and development of animals

Larva

sexually immature and morphologically distinct from the adult

metamorphosis

larvas undergo what stage to become a juvenile

juvenile

resembles an adult but is not yet sexually mature

Hox genes

these are a class of homeotic genes that provide positional information during animal embryonic development

true

TRUE OR FALSE: although the hox family of genes has been highly conserved, it can produce a wide diversity of animal morphology.

oxygenic photosynthesis

2.7 billion years ago, O2 began accumulating in the atmosphere. O2 is produced by which?

Eukaryotes

These organisms have a nuclear envelope, mitochondria, endoplasmic reticulum, and a cytoskeleton

Endosymbiont theory

The process of a prokaryotic cell gained entry to another prokaryotic cell that later on became a single organism.

Choanoflagellates

A group of protists that morphological and molecular evidence points to as the closest living relatives to animals

Molecular analysis

This revealed similarities between genes coding for proteins involved in adherence and attachment in choanoflagellates and animals.

Cambrian explosion

Marks the earliest fossil appearance of many major groups of living animals

Bilaterally symmetric form, complete digestive tract, and one way digestive system.

Traits of bilaterians from the cambrian explosion

New predator-prey relationships, a rise in atmospheric oxygen, and the evolution of the Hox gene

Hypotheses regarding the cambrian explosion and decline of ediacaran biota

body plan

a set of morphological and developmental traits

Radial symmetry

symmetry of animals with no front and back, or left and right

Bilateral symmetry

two-sided symmetry

Dorsal

refers to the top part of an animal

Ventral

refers to the bottom part or an animal with bilateral symmetry

Anterior

refers to the front part of an animal with a bilateral symmetry

posterior

refers to the back part of an animal with a bilateral symmetry

Radial animals

These kind of animals are often sessile or planktonic (drifting and weakly swimming)

Bilateral animals

These animals often move actively and have a central nervous system

Tissues

collections of specialized cells isolated from others by membranous layers

Ectoderm

the germ layer covering the embryo’s surface

Endoderm

the innermost germ layer and lines the developing digestive tube, called the archenteron

Diploblastic animals

These animals have both ectoderm and endoderm, inckuding cnidarians

Triploblastic animals

These animals, including all bilaterians, have an intervening mesoderm layer

Coelom

True body cavity derived from mesoderm

Coelomates

animals that possess a true coelom

pseudocoelom

a body cavity derived from the mesoderm and endoderm

Pseudocoelomates

triploblastic animals that possess a psedocoelom

Acoelomates

triploblastic animals that lack a body cavity

blastopore

forms during gastrulation and connects the archenteron to the exterior of the grastula

Protostome development

In which development does the blastopore becomes the mouth

deuterostome development

in which development does the blastopore become the anus

Deuterostomia

Clade that includes hemichordates, echinoderms, and chordates, as well as vertebrates and invertebrates.

Ecdysozoa

a clade of invertebrates that shed their exoskeletons through a process called ecdysis

Lophotrochozoa

Cades that account for more than 95% of known animal species.

Epithelial tissues

cell fit closely together and often form sheets

iii. and iv.

iii. Should be rests on basement membrane

iv. epithelial tissues regenerate easily

Which amongst the following are false:

i. Epithelial tissues are avascular, meaning there are no blood supply

ii. Epithelial tissues have two classification: simple and stratified

iii. The lower surface of epithelial tissues rest on an apical membrane

iv. Epithelial tissues do not regenerate easily which is why they are sensitive

Squamous (flattened), Cuboidal (cube-shaped), Columnar (column-like)

Enumerate the shapes of epithelial tissues

allows passage of materials by diffusion and filtration

location: Air sacs of the lungs, kidney glomeruli, lining of heart, blood vessels, and lymphatic vessels.

What is the function of simple squamous epithelial cells and where are these located

Location: Kidney tubules, ducts and small glands, and surface of ovary

Function: Secretion and absorption

function and location of simple cuboidal ephitelial cells

Location: Lines digestive tract, mucus-producing goblet cells, gallbladder, and excretory ducts of some glands

Function: Absorption, enzyme secretion

location and function of simple columnar epithelial tissues

Pseudostratified

Single layer, but some cells are shorter than others. Often looks like a double layer of cells, but they are not.

Location: Lines bronchi, uterine tubes, and some regions of the uterus.

Function: Propels mucus or reproductive cells by ciliary action.

location and function of Pseudostratified tissue

Stratified squamous

Cells at the apical surface are flattened. Consists of many layers of cells. Found as a protective covering where friction is common

Location: Lines esophagus, mouth, and vagina. Keratinized variety lines the surface of the skin.

Function: Protects underlying tissues in areas subject to abrasion.

location and function of stratified squamous tissues

stratified cuboidal

two layers of cuboidal cells. usually confined to the lining of the larger excretory ducts of exocrine glands

Transitional epithelium

Shape of cells depends upon the amount of stretching. Lines organs of the urinary system

Connective tissues

Found everywhere in the body. Includes the most abundant and widely distributed tissues

Binds body tissues together, Supports the body, Provides protection

functions of connective tissues

Collagenous fibers

connective tissue fiber that provides strength and flexibility

Reticular fibers

connective tissue fiber that join connective tissue to adjacent tissues

Elastic fibers

connective tissue fiber that stretch and snap back to their original length

fibroblasts

connective tissue cells that secrete the protein of extracellular fibers

Macrophages

Connective tissue cells that are involved in the immune system

loose connective tissue

Major type of connective tissue that binds epithelia to underlying tissues and holds organs in place

fibrous connective tissue

major type of connective tissue that is found in tendons and ligaments

tendons

these attaches muscles to bones

ligaments

these connect bones at joints

Bone

major type of connective tissue that is mineralized and forms skeleton

blood

major type of connective tissue that forms cell fragments in blood plasma

Cartilage

major type of connective tissue that is strong and flexible suppor material

Adipose

major type of connective tissue that stores fat for insulation and fuel

• osteocytes that lie in lacunae

• hard matrix of calcium salts

• large numbers of collagen fibers

Osseous tissues are composed of:

Cartilage

A hard yet flexible tissue that supports structures such as the outer ear and forms the entire skeleton of animals such as sharks and rays

Hyaline cartilage

Most common type of cartilage composed of abundant collagen fibers and rubbery matrix

Location: Forms embryonic skeleton; covers ends of long bones; and forms cartilage of nose, trachea, and larynx.

• Function: Support and reinforcement

location and function of hyaline cartilage

Elastic cartilage

type of cartilage that provides elasticity and can be seen in the external ear and epiglottis

Fibrocartilage

type of cartilage that is highly compressible and absorbs compression shocks. Mostly seen in the knee joints

Areolar tissue

Most widely distributed loose connective tissue. Soft, pliable tissue like “cobwebs”. Functions as a packing tissue

Reticular connective tissue

Delicate network of interwoven fibers. Forms stroma (internal supporting network) of lymphoid organs

Skeletal muscle

type of muscle tissue that is responsible for voluntary movement

smooth muscle

type of muscle tissue that is responsible for involuntary body activities

Cardiac muscle

type of muscle tissue responsible for contraction of the heart

• striated

• multinucleate

• long and cylindrical

3 characteristics of skeletal muscles:

• one nucleus per cell

• striated

• branching (cells are attached to other cardiac muscle cells)

3 characteristics of cardiac muscle:

• No visible striations

• One nucleus per cell

• Spindle-shaped cells

3 characteristics of smooth muscle:

Nervous tissues

Type of tissue that is composed of neurons and nerve support cells. Function is to send impulses to other areas of the body

Neurons

part of the nervous tissue that transmit nerve impulses

Glial cells

cells in the nervous tissue that support cells

Endocrine system

Transmits chemical signals called hormones to receptive cells throughout the body via blood

hormones

relatively slow acting, but can have long-lasting effects and can affect one or more regions throughout the body.

Nervous system

a system that transmits information between specific locations

Homeostasis

used to maintain a steady state or internal balance regardless of external environment

positive feedback

amplifies a stimulus and does not usually contribute to homeostasis in animals

circadian rhythm

governs physiological changes that occur roughly every 24 hours

Thermoregulation

the process by which animals maintain an internal temperature within a tolerable range

Acclimatization

a process by which homeostasis can adjust to changes in external environment