Bio Semester 2 Final Exam

virus

Particle made of proteins, nucleic acids, and sometimes lipids that can replicate only by infecting living cells.

capsid

Protein coat surrounding a virus.

lytic infection

Type of infection in which a virus enters a cell, makes copies of itself, and causes the cell to burst.

bacteriophage

Kind of virus that infects bacteria.

lysogenic infection

Type of infection in which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA.

prophage

Bacteriophage DNA that is embedded in the bacterial host's DNA.

retrovirus

RNA virus that contains RNA as its genetic information.

prokaryote

Unicellular organism that lacks a nucleus.

vaccine

Preparation of weakened or killed pathogens used to produce immunity to a disease.

envelope

Some viruses have these; if a virus does not have one of these, it is called a naked virus.

reverse transcriptase

Enzyme used to make DNA from an RNA template.

primary immune response

The body's first reaction to a foreign substance, or antigen.

secondary immune response

The body's immune system's reaction to an antigen that has been encountered before; this one is much faster.

cell

Basic unit of life.

cell theory

Fundamental concept of biology that states all living things are composed of cells, that cells are the basic units of structure and function in living things, and new cells are produced from existing cells.

cell membrane

Thin, flexible barrier that surrounds all cells; regulates what enters and leaves the cell.

nucleus

In cells, the structure that contains the cell's genetic material in the form of DNA.

eukaryote

Organisms whose cells contain a nucleus.

cytoplasm

Fluid portion of the cell outside the nucleus.

organelle

Specialized structure that performs important cellular functions within a eukaryotic cell.

ribosome

Cell organelle consisting of RNA and protein found throughout the cytoplasm in a cell; the site of protein synthesis.

endoplasmic reticulum

Internal membrane system found in eukaryotic cells; place where lipid and protein components of the cell membrane are assembled.

Golgi apparatus

Organelle in cells that modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or release outside the cell.

vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates.

lysosome

Cell organelle that breaks down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.

cytoskeleton

Network of protein filaments in a eukaryotic cell that gives the cell its shape and internal organization, and is involved in movement.

chloroplast

Organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy.

mitochondrion

Cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use.

cell wall

Strong, supporting layer around the cell membrane in some cells.

lipid bilayer

Flexible double-layered sheet that makes up the cell membrane and forms a barrier between the cell and its surroundings.

selectively permeable

Property of biological membranes that allows some substances to pass across it while others cannot.

homeostasis

Relatively constant internal physical and chemical conditions that organisms maintain.

diffusion

Process by which particles tend to move from an area where they are more concentrated to an area where they are less concentrated.

facilitated diffusion

Process of diffusion in which molecules pass across the membrane through cell membrane channels.

aquaporin

Water channel protein in a cell.

osmosis

Diffusion of water through a selectively permeable membrane.

isotonic

When the concentration of two solutions is the same.

hypertonic

When comparing two solutions, the solution with greater concentration of solutes.

hypotonic

When comparing two solutions, the solution with the lesser concentration of solutes.

osmotic pressure

Pressure that must be applied to prevent osmotic movement across a selectively permeable membrane.

homologous

Pairs of chromosomes that contain the same genes in the same order and locations along their length.

diploid

Means double; a cell that has two sets of homologous chromosomes.

haploid

Having a single set of chromosomes, this is the amount in gametes of sexually reproducing organisms.

meiosis

The making of gametes; the process in which the number of chromosomes per cell is cut in half.

tetrad

The structure containing four chromatids that forms during meiosis, specifically during prophase I.

crossing over

During prophase I, when the tetrads form, bits and pieces of the homologous chromosomes can be exchanged.

puberty

The developmental time in life when a child experiences physical and hormonal changes that mark a transition into adulthood.

testes

A pair of oval shaped glands in the scrotum that produce sperm and male hormones.

semiferous tubules

Coiled, threadlike structures inside the testes that are essential for reproduction; the site of spermatogenesis.

epididymis

A narrow, tightly coiled tube that's attached to the back of each testicle; provides a storage site for immature sperm.

penis

The male organ used for urination and sexual intercourse.

urethra

A tube that allows urine to exit the body from the bladder during urination.

vas deferens

A muscular tube that transports sperm from the epididymis to the urethra.

prostate gland

A gland in the male reproductive system that produces a fluid that nourishes and transports sperm.

ovary

An assigned at birth female reproductive organ in animals.

fallopian tube

Another term for oviducts; a pair of muscular, J-shaped ducts in the female reproductive system.

oviducts

Another term for fallopian tubes; a pair of muscular, J-shaped ducts in the female reproductive system.

uterus

A hollow, pear-shaped, muscular organ in a woman's pelvis that serves several reproductive functions.

cervix

A vital part of the female reproductive tract, located at the base of the uterus.

vagina

A muscular, elastic tube that's a vital part of the female reproductive system.

menstruation

The shedding of the lining of the uterus and vaginal bleeding that occurs in women.

first trimester

The period from conception to 12 weeks, marking the most changes in the embryo.

second trimester

Represents the middle part of your pregnancy, from weeks 13 to 26.

third trimester

The period between 28 and 42 weeks of gestation.

placenta

An organ that connects a developing fetus to the uterine wall during pregnancy.

gamete

A reproductive cell that fuses with another gamete during sexual reproduction.

zygote

A single cell that results from the fertilization of an egg by a sperm.

transformation

Process in which one strain of bacteria is changed by a gene or genes from another strain.

base pairing

Principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine.

nucleotide

Monomer of DNA, consists of a sugar, phosphate group, and a nitrogenous base.

nitrogen base

Four types in DNA: adenine, thymine, cytosine, and guanine.

phosphate group

Negatively charged groups found in the DNA backbone.

deoxyribose sugar

Type of sugar in DNA that connects to the phosphate group and nitrogen base.

ribose sugar

Type of sugar in RNA that connects to the phosphate group and nitrogen base.

DNA

Self-replicating material that is the main constituent of chromosomes.

RNA

Single-stranded molecule that acts as a messenger carrying instructions from DNA.

DNA Replication

Process of copying DNA prior to cell division.

Telomer

Repetitive DNA at the end of a eukaryotic chromosome.

DNA polymerase III

Principle enzyme involved in DNA replication.

DNA ligase

An enzyme that joins DNA strands together.

DNA helicase

Enzyme that separates the two strands of a DNA molecule.

RNA primer

A short strand of single-stranded nucleic acid that acts as a starting point for DNA synthesis.

Single stranded binding proteins (SSBP)

Proteins that keep the single stranded DNA from breaking down.

Leading strand

One of two new DNA strands that are synthesized during DNA replication in the same direction as the replication fork.

Lagging strand

This strand is synthesized in small fragments, called Okazaki fragments.

Okazaki Fragments

Short DNA pieces that form during the discontinuous replication.

mRNA

Single-stranded RNA that carries genetic information from DNA to the cytoplasm.

tRNA

A small RNA molecule that acts as a link between mRNA and amino acids.

rRNA

Non-coding RNA that is a key component of ribosomes.

transcription

Process of copying a segment of DNA into RNA.

translation

Process in which proteins are produced using RNA molecules as templates.

intron

Non-coding DNA sequence within a gene that is removed before translation.

exon

A section of a gene that is part of the mature RNA produced by that gene.

mammals

Members of the group of vertebrate animals whose young are nourished with milk.

primates

Distinguished from other mammals by their large brains, flat faces, and grasping hands.

homonin

The group consisting of modern humans and all our immediate ancestors.

multiregional hypothesis

Suggests that Homo sapiens evolved from multiple groups of Homo erectus in different parts.

out of Africa Hypothesis

Suggests humans evolved in Africa and then migrated out to populate the rest of the world.