Honors Biology Midterm Review Guide

biology
the science that seeks to understand the living world

cell
a collection of living matter enclosed by a barrier that separates the cell from its surroundings

sexual reproduction
cells from two different parents unite to produce the first cell of a new organism

asexual reproduction
the new organism has a single parent

metabolism
combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life process

stimulus
a signal to which an organism responds

homeostasis
process by which organisms keep internal conditions (temperature and water content) fairly constant to survive

evolution
change in a kind of organism over time

Describe some characteristics of living things
organized, adapt, evolve, adjust to surroundings, made up of units called cells, reproduce, based on a universal genetic code, grow and develop, obtain and use materials and energy, respond to their environment, change over time

Explain how life can be studied at different levels
life can be studied form molecules- cells- group of cells (tissue, organs, organ systems)- organisms- population- community- ecosystem- biosphere

monomer
smaller units that join together to form polymers

polymer
large compound formed from combinations of many monomers

carbohydrate
compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body

monosaccharide
single sugar molecules

polysaccharide
large macromolecules formed from monosaccharides

lipid
monosaccharides made mostly from carbon and hydrogen atoms; including fats, oils, and waxes

nucleic acid
macromolecules containing hydrogen, oxygen, nitrogen, cardon, and phosphorus

nucleotide
monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

ribonucleic acid (RNA)
one kind of nucleic acids containing sugar ribose

deoxyribonucleic acid (DNA)
one kind of nucleic acids containing sugar deoxyribose

protein
macromolecule that contains carbon, hydrogen, oxygen, and nitrogen

amino acid
compounds with an amino group (-NH2) on one end and a carboxyl; group (-COOH) on the other end

chemical reaction
process that changes one set of chemicals into another set of chemicals

reactant
element or compound that enters into a chemical reaction

product
element or compound produced by a chemical reaction

activation energy
energy needed to get a reaction started

catalyst
substance that speeds up the rate of a chemical reaction

enzyme
protein that acts as a biological catalyst

substrate
reactant of an enzyme-catalysts reaction

Describe the functions of each group of organic compounds
carbs-main source of energy; lipids-energy and cell membranes; nucleic acid-store and transmit hereditary information; proteins-control the rate of reactions, regulate cell processes, used to form bones and muscles, help fight disease

Explain how chemical reactions affect chemical bonds in compounds
they break and reform bonds taking in and releasing energy

Describe how energy changes affect how easily a chemical reaction will occur
the higher the activation energy of a reaction the harder it will be for the reaction to occur

Explain why enzymes are important to living things
they decrease activation energy

cell
the basic units of life

cell theory
the idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing ones

nucleus
in cells, structure that contains the cells genetic material (DNA) and controls the cell’s activities

eukaryote
organism whose cells contain nuclei

prokaryote
unicellular organism lacking a nucleus

organelle
specialized structure that preforms important cellular functions within a eukaryotic cell

cytoplasm
material inside the cell membrane – not including the nucleus

nuclear envelope
layer of two membranes that surrounds the nucleus of a cell

chromatin
granular material visible within the nucleus

chromosome
threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next

nucleolus
small, dense region within most nuclei in which the assembly of proteins begins

ribosome
small particle in the cell on which proteins are assembled; made of RNA and protein

endoplasmic reticulum
internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified

Golgi apparatus
stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

lysosome
cell organelle filled with enzymes needed to break down materials in the cell

vacuole
cell organelle that stores materials such as water, salts, proteins, and carbohydrates

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

chloroplast
organelle found in cells of plants and some other organisms that captures the energy from sunlight into chemical energy

cytoskeleton
network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement

centriole
one of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope

cell membrane
thin, flexible barrier around a cell; regulates what enters and leaves the cell

cell wall
strong supporting layer around the cell membrane in plants, algae, and some bacteria

lipid bilayer
doubled-layered sheet that forms to the core of nearly all cell membranes

concentration
the mass of solute in a given volume of solution, or mass/volume

diffusion
process by which molecules tend to move from and area where they are more concentrated to an area where they are less concentrated

equilibrium
when the concentration of a solute is the same throughout a solution

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 the greater concentration of solutes

hypotonic
when comparing two solutions, the solution with the lesser concentration of solutes

facilitated diffusion
movement of specific molecules across cell membranes through protein channels

active transport
energy-requiring process that moves material across a cell membrane against a concentration difference

endocytosis
process by which a cell takes material into the cell by in folding of the cell membrane

phagocytosis
process in which extensions of cytoplasm surround and engulf large particles and take them into the cell

pinocytosis
process by which a cell takes in liquid from the surrounding environment

exocytosis
process by a cell releases large amounts of material

cell specialization
process in which cells develop in different ways to preform different tasks

tissue
group of similar cells that preform a particular task

organ
group of tissues that work together to preform closely related functions

organ system
group of organs that work together to preform a specific function

Explain what the cell theory is
all living things are composed of cells; cells are the basic unit of structure and function in living things; new cells are produced from existing cells

Describe how researchers explore the living cell
by using different microscopes- transmission- see cell structure; scanning- see surface of the cell

Distinguish between eukaryotes and prokaryotes
eukaryote-cell that contain nuclei, organelles, most multicellular organisms; prokaryote-doesn’t contain nuclei, no organelles, unicellular organisms

Describe the function of the cell nucleus
controls activities of organelles; has directions to make proteins

Describe the functions of the major cell organelles
nucleolus- makes ribosomes; ribosomes- assembles proteins; cytoplasm- suspends organelles and site of chemical reactions; endoplasmic reticulum- site of reactions; Golgi apparatus- modifies proteins and sends them to appropriate destinations; vacuole- stores materials; lysosomes- digest excess or worn-out organelles, food, and engulfs viruses and bacteria; chloroplasts- capture light energy and site of photosynthesis; mitochondria- transforms energy in food into ATP; cilia- used to move and obtain food; flagella- propel cells

Identify the main roles of the cytoskeleton
support and maintain shape, movement

Identify the main functions of the cell membrane and the cell wall
cell wall- supports and protects cell; cell membrane- regulates what enters and leaves the cell and also provides protection and support

Describe what happens during diffusion
particles move from an area where they are more concentrated to an area where they are less concentrated

Explain the process of osmosis, facilitated diffusion, and active transport
osmosis- diffusion of water; facilitated diffusion- movement of specific molecules across cell membranes through protein channels; active transport- energy requiring process that moves material across a cell membrane against a concentration difference

Describe cell specialization
cell become specialized for a function in the organism

Identify the organization levels in multicellular organisms
cells, tissues, organs, organ systems

autotroph
organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds also called a producer

heterotroph
organism that obtains energy from the food it consumes, also called a consumer

adenosine triphosphate
one of the principle chemical compounds that living things use to store and release energy

photosynthesis
process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high energy carbohydrates such as sugars and starches

chlorophyll
principle pigment of plants and other photosynthetic organisms captures light energy

thylakoid
saclike photosynthetic membrane found in chloroplasts

photosystem
light-collecting units of the chloroplasts

stroma
region outside the thylakiod membranes in chloroplasts

NADP+
one of the carrier molecules that transfers high-energy electrons from chlorophyll to other molecules

light-dependent reactions
reactions of photosynthesis that use energy from light to produce ATP and NADPH

ATP synthase
large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Calvin cycle
reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars

Explain where plants get the energy they need to produce food
sunlight- use photosynthesis into glucose

Describe the role of ATP in cellular activities
easy energy source; energy stored in bonds between second and third phosphate group

State the overall equation for photosynthesis
6CO2+6H2O+light=C6H12O6+6O2

Describe the role of light and chlorophyll in photosynthesis
the pigment chlorophyll traps light in the chloroplasts- light is used to break down H2O for use in the light dependent reaction

Describe the structure and function of a chloroplast
chloroplasts contain granum which are stacks of thylakoid disks; the spaces between and around the granum is known as the stroma; chloroplast is where photosynthesis takes place

Describe what happens in the light-dependent reactions
light energy breaks H2O into H+, O2, and high energy e-; e- is passed down the e- transport chain and eventually makes NADPH; H+ is passed through ATP synthase to form ATP molecules

Explain what the Calvin cycle is
process of forming a 6 carbon carbohydrate from CO2

Identify factors that affect the rate at which photosynthesis occurs
temperature, light intensity, and H2O

calorie
amount of energy needed to raise the temperature of one gram of water by one degree Celsius

glycolysis
first step in releasing the energy of glucose, in which a molecule of glucoseis broken into 2 molecules of pyruvic acid

cellular respiration
process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

NAD+
electron carrier involved in glycolysis

fermentation
process by which cells release energy in the absence of oxygen

anaerobic
process that does not require oxygen

aerobic
process that requires oxygen

Krebs cycle
second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extractiong reactions

electron transport chain
a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP to ATP

Explain what cellular respiration is
process of changing carbohydrates into energy

Describe what happens during the process of glycolysis
6 carbon carbohydrate is broken down into 2 pyruvic acids; 4 ATP (net 2) and 2 NADH is made

Name the two main types of fermentation
alcoholic and lactic acid

Describe what happens during the Krebs cycle
pyruvic acid combines with a 4 carbon compound, broken apart, and produces 4 NADH, 1 FADH2, and 1 ATP

Explain how high-energy electrons are used by the electron transport chain
high-energy electrons are passed down the e- transport chain causing H+ to flow to the outside of the mitochondrial membrane; as H+ flows n again they pass through ATP synthase creating ATP

Identify the three pathways the body uses to release energy during exercise
lactic acid fermentation, cellular respiration, glycolysis

Compare photosynthesis and cellular respiration
photosynthesis- make glucose, store energy, use CO2 and H2O, gives off O2; respiration- breaks down glucose, releases energy, uses O2, gives off H2O and CO2

cell division
Process by which a cell divides into two new daughter cells

mitosis
Part of eukaryotic cell division during which the cell nucleus divides

cytokinesis
Division of the cytoplasm during cell division

chromatid
1 of 2 sister parts of a duplicated chromosomes

centromere
area where the chromatids of a chromosome are attached

interphase
stage in between cell division

cell cycle
series of events that cells go through as they grew and divides

prophase
first and longest phase of mitosis during which the chromosomes become visible and the centrioles separate and take up opposite sides of the nucleus

centriole
one of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope

spindle
fanlike microtubule structure that helps separate the chromosome during mitosis

metaphase
second phase of mitosis, during which the chromosomes line up across the center of the cell

anaphase
the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

telophase
fourth and final stage of mitosis, during which the chromosomes begin to disperse into a triangle of dense material

cyclin
one of a family of closely related proteins that regulate the cell cycle in eukaryotic cells

cancer
disorder in which some of the body’s own cells lose the ability to control growth

Explain the problems that growth causes for cells
effective diffusion, not enough DNA, surface area to volume ratio is too great

Describe how cell division solves the problems of cell growth
keeps cell size down

Name the main events of the cell cycle
interphase (G1, S, G2), cell division-mitosis and cytokinesis

Describe what happens during the four phases of mitosis
prophase- chromosomes condense, nucleus disappears, centrioles migrate, spindles form; metaphase- sister chromatids lineup down center; anaphase- sister chromatids split apart and are pulled toward centrioles; telophase- chromatids reach opposite poles, nucleus reforms, chromosomes unwind

Identify a factor that can stop cells from growing
cyclin

Describe how the cell cycle is regulated
by both internal (regulatory proteins) and external (surface proteins) regulators

Explain how cancer cells are different from other cells
they have uncontrolled cell division

genetics
Scientific study of heredity

fertilization
Process in sexual reproduction in which male and female reproductive cells join to form a new cell

true-breeding
Term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate

trait
Specific characteristics that varies from one individual to another

hybrid
Offspring of crosses between parents with different traits

gene
Sequence of DNA that codes for a protein and thus determines a trait

allele
One of a number of different forms of a gene

segregation
Separation of alleles during gamete formation

gamete
Specialized cell involved in sexual reproduction

probability
Likelihood that a particular event will occur

Punnett square
Diagram showing the gene combinations that might result from a genetic cross

homozygous
Term used to refer to an organism that has two identical alleles for a particular trait

heterozygous
Term used to refer to an organism that has two different alleles for the same trait

phenotype
Physical characteristics of an organism

genotype
Genetic makeup of an organism

independent assortment
Independent segregation of genes during the formation of gametes

incomplete dominance
Situation in which one allele is not completely dominant over another

codominance
Situation in which both alleles of a gene contribute to the phenotype of the organism

multiple alleles
Three or more alleles of the same gene

polygenic traits
Trait controlled by two or more genes

homologous
Term used to refer to chromosomes that have a corresponding chromosome from the opposite-sex parent

diploid
Term used to refer to a cell both sets of homologous chromosomes

haploid
Term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of chromosomes

meiosis
Process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

tetrad
Structure containing four chromatids that forms during meiosis

crossing-over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis

Describe how Mendel studied inheritance in peas
by crossing pea plants of similar traits

Summarize Mendel’s conclusion about inheritance
traits are inherited from the parent generation- each parent gives 1 alleles

Explain the principle of dominance
some alleles are dominant and others recessive

Describe what happens during segregation
alleles separate independently during gamete formation

Explain how genetics use the principles of probability
use to predict the outcomes of a genetic cross

Describe how genetics use Punnett squares
to predict and compare genetic variations that will result from a cross

Explain the principle of independent assortment
genes of different traits segregate independently during the formation of gametes

Describe other inheritance patterns
incomplete dominance- blending of phenotypes; codominance- both phenotypes expressed; multiple alleles- more than 2 alleles for a trait; polygenic traits- trait controlled by multiple chromosomes

Explain how Mendel’s principles apply to organisms
all organisms follow these same rule and principles for inheritance

Contrast the chromosome number of body cells and gametes
body cells- 2N (diploid); gametes- N (haploid)

Summarize the events of meiosis
meiosis 1- number of chromosomes in each cell splits in half and crossing over occurs (prophase 1) to increase genetic variations; meiosis 2- gametes decrease in size and increase in number

Contrast meiosis and mitosis
Meiosis- 2 phases, chromosomes number decreases, sex cells; mitosis- 1 phase, chromosomes number is same, body cells

nucleotide
monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

base pairing
principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine

chromatin
granular material visible within the nucleus; consists of DNA tightly coiled around proteins

histone
protein molecule around which DNA is tightly coiled around chromatin

replication
coping process by which a cell duplicates its DNA

DNA polymerase
enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

gene
sequence of DNA that codes for a protein and thus determines a trait

messenger RNA
RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

ribosomal RNA
type of RNA that makes up the major part of ribosomes

transfer RNA
type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

transcription
process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA

RNA polymerase
enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

promoter
region of DNA that indicates to an enzyme where to bind to make RNA

intron
sequence of DNA that is not involved in coding for a protein

exon
expressed sequence of DNA; codes for a protein

codon
three-nucleotide sequence on a messenger RNA that codes for a single amino acid

translation
decoding of mRNA message into a polypeptide chain

anticodon
group of three brothers on a tRNA molecule that are complementary to an mRNA codon

mutation
change in a DNA sequence that affects genetic information

point mutation
gene mutation involving changes in one of a few nucleotide

frameshift mutation
mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide

polyploidy
condition in which an organism has extra sets of chromosomes

Summarize the relationship between genes and DNA
genes coded by sequences of DNA

Describe the overall structure of the DNA molecule
deoxyribose, phosphate group, nitrogen base

Summarize the events of DNA replication
DNA molecule separates into 2 strands, then 2 new complementary strands following the rule of base pairing; each strand of double helix of DNA serves as a template, or model for the new strand

Relate the DNA molecule to chromosome structure
chromosomes are made of strands of DNA

Tell how RNA differs from DNA
DNA- thymine, double strand, housed in the nucleus; RNA- uracil, single strand, moves in and out of nucleus

Name the three main types of RNA
mRNA- copy made from DNA to take to ribosomes; rRNA- part of ribosome; and tRNA- brings amino acids to ribosomes

Describe transcription and the editing of RNA
RNA copy is made from a DNA strand inside the nucleus

Identify the genetic code
genetic code is made of a sequence of codons

Summarize translation
mRNA codes for specific amino acids which are coded by codons; corresponding anticodons on tRNA carry amino acids attach to mRNA to create a chain of amino acids=protein

Explain the relationship between genes and proteins
genes code for specific proteins

Contrast gene mutations and chromosomal mutations
gene- changes specific codons; chromosomal- changes different genes on chromosomes

selective breeding
method of breeding that allows only those individual organisms with desired characteristics to produce the next generation

hybridization
breeding technique that involves crossing dissimilar individuals to bring together the best traits of both organisms

inbreeding
continued breeding of individuals with similar characteristics to maintain the desired characteristics if a line of organisms

transgenic
term used to refer to an organism that contains genes from other traits

clone
member of a population of genetically identical cells produced from a single cell

karyotype
photograph of chromosomes grouped in order in pairs

sex chromosome
one of two chromosomes that determine an individual’s sex

autosome
chromosome that is not a sex chromosome

pedigree
chart that shows the relationships within a family

sex-linked gene
gene located on the X or Y chromosome

nondisjunction
error in meiosis in which homologous chromosomes fail to separate

DNA fingerprinting
analysis of sections of DNA that have little or no known function, but vary widely from one individual to another, in order to identify individuals

Explain the purpose of selective breeding
carry specific traits

Describe two techniques used in selective breeding
hybridization- crossing dissimilar individuals to bring together the best of both organisms; inbreeding- continue breeding of individuals with similar characteristics

Describe the usefulness of some transgenic organisms to humans
bacteria that can produce human insulin; make larger animals; make healthier plants

Summarize the main steps in cloning
fuse a body cell with the egg of a sheep

Identify the types of human chromosomes in a karyotype
44 autosomes and 2 sex chromosomes

Explain how sex is determined
by sex chromosomes

Explain how pedigrees are used to study human traits
different traits can be tracked down a family tree

Describe examples of the inheritance of human traits
blood group genes (multiple alleles and dominate/recessive)

Explain how small changes in DNA cause genetic disorders
changes in DNA change different proteins that are coded for

Identify characteristics of human chromosomes
omit

Describe some sex-linked disorders and explain why they are more common in males than in females
color blindness; hemophilia; muscular dystrophy; more common in males because even if it is recessive it will be expressed

Explain the process of the X-chromosome inactivation
1 X- chromosome in females is randomly switched off creating a Barr-body

Summarize nondisjunction and the problems it causes
homologous chromosomes fail to separate during the first stage of meiosis; can cause down syndrome (trisomy 21), turners (women with 1 X), and Klinfeltes (man with 2 X’s)

Summarize methods of human DNA analysis
testing for alleles and DNA fingerprinting

State the goal of the Human Genome Project
analyze the human DNA sequence

Describe how researchers are attempting to cure genetic disorders
absent or faulty genes are replaced by working genes

taxonomy
Discipline of classifying organisms and assigning each organism a universally accepted name

binomial nomenclature
Classification system in which each species is assigned a two-part scientific name

taxon
Group or level of organization into which organisms are classified

species
Some description of a characteristic of that animal

genus
Group of closely related species and the first part of the scientific name in binomial nomenclature

family
Group of genera that share many characteristics

order
Group of similar families

class
Group of similar orders

phylum
Group of closely related classes

kingdom
Large taxonomic group, consisting of closely related phyla

phylogeny
Evolutionary relationships among organisms

evolutionary classification
The strategy of grouping organisms together based on their characteristics

derived character
Characteristics that appear in recent parts of a lineage but not in its older members

cladogram
A diagram that shows the evolutionary relationships among a group of organisms

molecular clock
A model that uses DNA comparisons to estimate the length of time that two species have been evolving independently

domain
An inclusive taxonomic category that is bigger than a kingdom

Bacteria
Domain of unicellular prokaryotes that have rigid cell walls containing peptidoglycan

Eubacteria
Kingdom of unicellular prokaryotes whose cell walls are made up of peptidoglycan

Archaea
Domain of unicellular prokaryotes that have cell walls do not contain peptidoglycan and live in extreme environments

Archaebacteria
Kingdom of unicellular prokaryotes whose cell walls do not contain peptidoglycan

Eukarya
Domain of all organisms whose cells have nuclei, including protists, plants, fungi, and animals

Protista
Kingdom composed of eukaryotes that are not classified as plants, animals, or fungi, most diverse, most unicellular (some multicellular), and some photosynthetic, some heterotrophic

Fungi
Kingdom composed of heterotrophs, many obtain energy and nutrients from dead organic matter and most are multicellular (some unicellular)

Plantae
Kingdom of multicellular photosynthetic autotrophs that have cell walls containing cellulose and nonmotile

Animalia
Kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls, most can move at some point in their life cycle, and incredible diversity

Explain how living things are organized for study
they are organized into taxons- kingdom, phylum, class, family, genus, species

Describe binomial nomenclature
two word naming system- first word= genus; second word= species

Explain Linnaeus’s system of classification
based on similar characteristics

Explain how evolutionary relationships are important in classification
find out how organisms descended and who they are closely related to

Identify the principle behind cladistic analysis
look at new characteristics as they arrive in a lineage

Explain how we can compare very dissimilar organisms
we can look at DNA and RNA sequences

Name the six kingdoms of life as they are now identified
Eubacteria, Archaebacteria, Protists, Fungi, Plantae, Animalia

Describe the three-domain system of classification
Eubacteria- prokaryote with peptidoglycan in cell wall; Archaebacteria- prokaryote without peptidoglycan in cell wall; Eukarya- eukaryotes

What are the products of photosynthesis?
Oxygen and sugar

The energy of the electrons passing along the electron transport chain is used to make _________.
ATP

Where would you find photosystem I and II?
The thylakoid membrane

What are the products of the Calvin Cycle?
High-energy sugar

Where do light-dependent reactions take place?
Within the thylakoid membrane

If an organisms diploid number is 18, what is it’s haploid number?
9

Cellular respiration uses 1 molecule of glucose to produce _______ molecules of ATP.
36

Which grows faster in a cell, surface area or volume?
volume

_______ is a disorder where the cell loses the ability to control growth and division.
Cancer

What happens to a cell when it comes into contact with another cell?
it stops growing

What is principle of independent assortment?
genes of different traits separate without influence on each other

What are the products of the light dependent reactions?
oxygen gas, ATP, and NADPH

What is the main function of the cytoskeleton?
help the cell keep its shape