question

The light reactions of photosynthesis use ____ and produce _____.

answer

water; NADPH

question

Where does photosynthesis take place?

answer

chloroplasts

question

What connects the two photosystems in light reactions?

answer

an electron transport chain

question

What two molecules are produced by light reactions and are used to power the Calvin cycle?

answer

NADPH and ATP

question

What provides electrons for the light reactions?

answer

H2O

question

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?

answer

CO2

question

What transports electrons from the light reactions to the Calvin cycle?

answer

NADPH

question

The light reactions take place in the ________ and the Calvin cycle takes place in the _______.

answer

thylakoid membrane; stroma

question

One of the important waste products of photosynthesis is oxygen gas. Where does this oxygen gas come from?

answer

Oxygen is released when water is broken down to extract electrons and protons for use in the light reactions.

question

The light reactions produce _______.

answer

oxygen, NADPH, ATP

question

Thylakoid membranes bring together the components necessary to carry out _____.

answer

light reactions

question

Incoming photons of light energy initiate photosynthesis by _____.

answer

exciting electrons in pigment molecules within the photosystems, raising them to a higher energy level

question

Which option properly summarizes the inputs and outputs of the Calvin cycle?

answer

ATP + NADPH + 3CO2 ( G3P

question

An earthworm that feeds on the remains of plants and animals is acting as a _____.

answer

detritivore

question

When a human eats a steak, the human is acting as a _____.

answer

secondary consumer

question

A cow eating grass is an example of a _____.

answer

primary consumer

question

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____.

answer

tertiary consumer

question

What name is given to the process by which detritivores return carbon to the atmosphere?

answer

decomposition

question

Which of these removes carbon from the atmosphere? logging trees, rabbits, burning fossil fuels, bobcats, algae

answer

algae

question

Detritus is composed of _____.

answer

dead organic matter and excreted wastes

question

An organism gets carbon by using carbon dioxide in the atmosphere to make sugar molecules. This organism is a

answer

producer

question

Which organisms play a role in returning carbon to the atmosphere?

answer

producers, consumers, decomposers

question

Every carbon atom in the organic molecules that make up your body MUST recently have been part of

answer

a producer

question

Imagine following a single carbon atom through the carbon cycle. Which of the following is a possible path for the carbon atom to take?

answer

The atmosphere, a plant, a herbivore, a decomposer, then back to the atmosphere

question

Which process or processes return carbon to the atmosphere?

answer

cellular respiration

question

Glycolysis is the only stage of cellular respiration that _____.

answer

requires ATP to make ATP

question

When proteins are used as a source of energy for the body, the proteins

answer

are converted mainly into intermediates of glycolysis or the citric acid cycle.

question

ATP is not produced during photosynthesis, but only during

answer

cellular respiration

question

A small group of 25 predatory birds populates an island. By chance, three members of the population have superior sight, which gives these birds a significant advantage in capturing prey. After hundreds of generations, the population on the island has risen to 1,500 and all of the birds have superior sight compared to the same species on other islands. This is an example of _____.

answer

evolutionary adaptation

question

Human somatic cells (mostly body cells) are

answer

diploid

question

Each somatic cell has two sets of

answer

23 chromosomes

question

A special kind of cell division called meiosis occurs in the ovaries and testes, producing _____

answer

haploid gametes- eggs and sperm- that carry only one set of 23 chromosomes each

question

Fertilization of an egg by a sperm combines two sets of chromosomes, producing a

answer

diploid zygote with 46 chromosomes

question

Meiosis produces _______ and fertilization produces ________.

answer

haploid gametes, diploid organisms

question

Meiosis is essential to sex, because it enables each parent to contribute

answer

one set of chromosomes to each diploid offspring

question

What happens during interphase before meiosis?

answer

chromosomes replicate

question

Unlike mitosis, where each chromosome is on its own, in meiosis I homologous chromosomes pair up, and each pair separates, producing

answer

two haploid cells with their sister chromatids still joined

question

Meiosis II is like _____.

answer

Mitosis Sister chromatids separate and four haploid cells are formed

question

Asexual reproduction is the process in which

answer

a single individual is reproducing

question

Gametes are produced by

answer

meiosis

question

Normal human gametes carry

answer

23 chromosomes

question

Once meiosis I is complete, cells are ______.

answer

haploid

question

A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.

answer

16

question

A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.

answer

False; Mitosis does indeed take place during M phase, but M phase is shorter than interphase; cells spend most of their time in interphase.

question

A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?

answer

24; DNA replication is completed during S phase, which occurs prior to G2 phase. Since each chromosome (12) is replicated, there are 24 DNA molecules in the nucleus during G2 phase.

question

Cell division occurs during this short phase, which generally involves two discrete processes: the contents of the nucleus (mainly the duplicated chromosomes) are evenly distributed to two daughter nuclei, and the cytoplasm divides in two.

answer

Mitotic Phase

question

DNA synthesis (or replication) occurs during this phase. At the beginning of the phase, each chromosome is single. At the end, after DNA replication, each chromosome consists of two sister chromatids.

answer

S phase

question

Typically, this phase accounts for 90% of the cell cycle. It is a time of high metabolic activity. The cell grows by producing proteins and organelles, and chromosomes are replicated.

answer

Interphase

question

Typically, this phase accounts for 90% of the cell cycle. It is a time of high metabolic activity. The cell grows by producing proteins and organelles, and chromosomes are replicated.

answer

Mitosis

question

This third subphase of interphase is a period of metabolic activity and growth. During this phase the cell makes final preparations for division.

answer

G2 phase

question

This is the portion of the cell cycle just after division, but before DNA synthesis. During this time the cell grows by producing proteins and organelles.

answer

G1 phase

question

This is the step in the cell cycle when the cytoplasm divides in two.

answer

Cytokinesis

question

During _____ both the contents of the nucleus and the cytoplasm are divided.

answer

the mitotic phase

question

During _____ the cell grows and replicates both its organelles and its chromosomes.

answer

interphase

question

What occurs during prophase?

answer

Mitotic spindle forming

question

What occurs during metaphase?

answer

Sister chromatids centered

question

What occurs during anaphase?

answer

Chromosomes separating

question

What occurs during telophase and cytokinesis?

answer

Nuclear envelops forming

question

What must happen before a cell can begin mitosis?

answer

The chromosomes must be duplicated.

question

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

answer

Prophase

question

The chromosomes line up in the center of the cell during which phase of mitosis?

answer

Metaphase

question

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?

answer

Anaphase

question

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?

answer

Telophase

question

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.

answer

Cytokinesis

question

A _____ is a lump of abnormal cells that, although growing out of control, remains at its original site.

answer

benign tumor

question

A _____ is an abnormally growing mass of cells that is actively spreading throughout the body.

answer

malignant tumor

question

_____ is the spread of cancer cells from their site of origin to other sights in the body

answer

Metastasis

question

An individual with a malignant tumor is said to have _____.

answer

cancer

question

The most common type of cancer is a _______; this type always originates in tissues that line organs.

answer

carcinoma

question

A normal gene that, if mutated, can lead to cancer is called a _________.

answer

proto-oncogene

question

A gene that causes a cell to become cancerous is called a(n) ______.

answer

oncogene

question

A(n) ______________ that encodes proteins that inhibit cell division. Such proteins normally help prevent cells from becoming cancerous.

answer

tumor-suppressor gene

question

A(n) ____________ is a protein that promotes cell division. In excess, such a protein may lead to cancer.

answer

growth factor

question

_____ is a carcinogen that promotes colon cancer.

answer

Fat

question

_____ is a carcinogen that promotes lung cancer.

answer

Smoking

question

______ is a carcinogen that promotes prostate cancer.

answer

Testosterone

question

______ is a carcinogen that promotes uterine cancer.

answer

Estrogen

question

______ is a carcinogen that promotes skin cancers.

answer

UV light

question

_____ are a carcinogen that promotes cancer of lymphatic cells (lymphomas).

answer

Viruses

question

Meiosis I produces _____ cells, each of which is _____.

answer

two; haploid

question

Meiosis II typically produces _____ cells, each of which is _____.

answer

four; haploid

question

During _____ sister chromatids separate.

answer

anaphase II

question

At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.

answer

telophase I

question

Synapsis occurs during _____.

answer

prophase I

question

Homologous chromosomes migrate to opposite poles during _____.

answer

anaphase I

question

During _____ chromosomes align single file along the equator of a haploid cell.

answer

metaphase II

question

At the end of _____ and cytokinesis there are four haploid cells.

answer

telophase II

question

During _____ a spindle forms in a haploid cell.

answer

prophase II

question

Meiosis starts with a single diploid cell and produces

answer

four haploid cells

question

A cell preparing to undergo meiosis duplicates its chromosomes during

answer

interphase

question

During prophase I of meiosis,

answer

homologous chromosomes stick together in pairs

question

The correct order of events during meiosis is

answer

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II

question

During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?

answer

prophase I

question

Mitosis goes on continuously in most parts of the body, whereas meiosis takes place only in

answer

the gonads

question

Meiosis I is the only time that chromosomes line up by

answer

homologous pairs

question

The centromere is the point of attachment between two

answer

duplicated chromosomes

question

Pairing of homologous chromosomes is followed by

answer

crossing over, the exchange of genetic material between nonsister chromatids of homologous chromosomes.

question

Asexual reproduction is a means of creating new individuals solely by

answer

mitosis, the form of cell division that creates genetically identical daughter cells

question

Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! Then you realize that this cell is

answer

undergoing cytokinesis

question

Mutations in the p53 gene can lead to cancer by

answer

causing the production of a faulty protein that is no longer able to inhibit cell division.

question

the conclusion of meiosis I, the daughter cells are _____.

answer

haploid and the sister chromatids

question

Crossing over is a phenomenon that creates genetic diversity during

answer

meiosis

question

Genetic diversity is enhanced by

answer

crossing over during meiosis, independent orientation of chromosomes at metaphase I and random fertilization

question

A ______ is an inherited feature that varies from individual to individual

answer

character

question

A ______ is one particular variation of a character.

answer

trait

question

A genetic cross involving parents that differ in a single character is called a

answer

monohybrid cross

question

Most human genes come in alternate forms called

answer

alleles.

question

If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the ______ allele.

answer

dominant

question

If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the ______ allele.

answer

recessive

question

The physical traits of an organism

answer

phenotype

question

The genetic makeup of an organism

answer

genotype

question

A cross between two individuals with black eyes and green skin which results in an individual with orange eyes and white skin is an example of a _____ cross.

answer

dihybrid

question

A phenotypic ratio of 9:3:3:1 in the offspring of a cross indicates that _____.

answer

both parents are heterozygous for both genes

question

In a situation in which genes assort independently, what is the ratio of the gametes produced by an AaBB individual?

answer

1 AB; 1 aB

question

(With some exceptions) DNA is a double-stranded molecule and RNA is a

answer

single-stranded molecule

question

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.

answer

1'......5'

question

Nucleic acids are assembled in the _____ direction.

answer

5' to 3'

question

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

answer

thymine.. cytosine

question

The central dogma describes how the genes in the nucleus work to produce an organism's phenotype. Another way of putting it is that the central dogma follows the flow of information from _____.

answer

DNA to protein

question

DNA carries out two basic functions in cells: (1) information storage and transfer (genes can be copied and passed to offspring) and (2) the "blueprint" function (genes provide instructions for building proteins). The key process for information storage and transfer to offspring cells is _____.

answer

DNA replication

question

A gene is a sequence of DNA nucleotide bases that codes for a single protein. Approximately how many nucleotide bases would be required to code for a protein chain that is 100 amino acids long?

answer

300

question

tRNA molecules work to _____.

answer

translate mRNA to produce a specific amino acid sequence

question

A particular gene does NOT constantly churn out the same protein at all times in every cell. This is true for two reasons. First, _____ can allow one gene to produce several different proteins. Second, genes are constantly being turned on and off through the process of _____.

answer

mRNA reprocessing...gene regulation

question

Short segments of newly synthesized DNA are joined into a continuous strand by _____.

answer

ligase

question

After DNA replication is completed, _____.

answer

each new DNA double helix consists of one old DNA strand and one new DNA strand

question

The action of helicase creates _____

answer

replication forks and replication bubbles

question

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

answer

it is more efficient than assembling completely new strands

question

An old DNA strand is used as a _____ for the assembly of a new DNA strand.

answer

template

question

How do mutations affect an organism?

answer

they may cause the development of a disease-causing allele, of a more beneficial allele, or may have no noticeable effect

question

DNA replication occurs at an unbelievably fast rate. Once replication is complete, we can expect to find a _____ number of mistakes.

answer

small

question

A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the:

answer

her egg cells

question

Which of the following would indicate a base pairing mutation in DNA?

answer

a G paired with a T

question

Replication occurs in the

answer

nucleus

question

Transcription occurs in the

answer

nucleus

question

Translation occurs in the

answer

ribosomes

question

An insect that has the genotype EeGGcc will have the same phenotype as an insect with the genotype _____.

answer

EEGgcc

question

Assume that in cattle a spotted coat is dominant to an even coat, short horns are dominant to long horns, and the traits for coat type and horn length assort independently. In a cross between cattle that are each heterozygous for both traits, what proportion of their offspring are expected to have long horns?

answer

1/4

question

You cross two fruit trees. One tree produces lemons with spiky leaves. The other produces limes with smooth leaves. Your F1 generation produces lemons with smooth leaves and spiky leaves. What are the genotypes of the parents? L = lemons; l = limes; S = smooth leaf; s = spiky leaf.

answer

LLss and llSs

question

We would expect that a 15-nucleotide sequence ending with a stop codon will direct the production of a polypeptide that consists of

answer

4 amino acids

question

Consider the following sequence and explain what effect the mutation has on the protein that is translated. UCUAUGUUUCACAGAGGGAAACCCUAACCC (wild type) UCUAUGUUUCACUGAGGGAAACCCUAACCC (mutant)

answer

prematurely stops the translation of the protein

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