Keystone Day 2 Review

Hypothesis

An educated guess (If...then statement)

Biosphere

The land, water and air on Earth

Theory

A hypothesis that is supported repeatedly may become this

Embryonic Stem Cells

The cells of an early developing organism that can become any cell

Dependent Variable

This variable goes on the y-axis

Control

An experimental set up the scientist uses to compare other results

Homeostasis

How organisms keep internal conditions stable

Observation

Process of noticing and describing events or processes in a careful, orderly way

Inference

A logical interpretation based on prior knowledge and experience

Hypothesis

Possible explanation for a set of observations or possible answer to a scientific question

Controlled Experiment

Experiment in which only one variable is changed

Independent Variable

Factor in a controlled experiment that is deliberately changed; also called the manipulated variable

Dependent Variable

Variable that is observed and that changed in response to the independent variable; also called the responding variable

Control Group

Group in an experiment that is exposed to the same conditions as the experimental group except for one independent variable

Theory

Well-tested explanation that unifies a broad range of observations and hypotheses, and enables scientists to make accurate predictions about new situations

DNA

Deoxyribonucleic acid; a self-replicating material present in nearly all living organisms as the main constituent of chromosomes; the carrier of genetic information.

Sexual Reproduction

Type of reproduction in which cell from two parents unite to form the first cell of a new organism

Asexual Reproduction

Process of reproduction involving a single parent that results in offspring that are genetically identical to the parent

Biosphere

Part of Earth in which life exists including land, water and air or atmosphere

Nucleus Structure

Chromatin \= DNA + Protein

Originally, energy in food comes from the \_____.

sun

Organisms that use light energy from the sun to produce food

Autotrophs (auto\=self)

Organisms that cannot use the sun's energy to make food

Heterotrophs

Energy decreases as you go up the energy pyramid because

The energy transfer is not 100% efficient and is lost in metabolism, waste and cellular processes only 10% is transferred

Who is credited with discovering the structure of DNA

James Watson and Francis Crick

The sugar found in DNA

deoxyribose

The two molecules that compose the backbone of DNA

phosphates and sugars (deoxyribose)

Complementary base pairs are held together in DNA by these

Hydrogen bonds

The main reason DNA would need to make a copy of itself

For a cell to reproduce

Enzyme that unzips the helix

(DNA) helicase

The DNA complement to: ATG CGT

TAC GCA

Unfolded DNA

Chromatin

Base Pairing

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

Replication

Process of copying DNA prior to cell division- Occurs in the S phase

What is the role of DNA?

Stores, copies and transmits information

Monomer of DNA

Nucleotides

What is the 5-carbon sugar in a nucleotide made of?

Deoxyribose

What are the four nitrogenous bases in DNA?

Adenine (A)
Guanine (G)
Thymine (T)
Cytosine (C)

What is the backbone of DNA formed by?

Sugars and phosphates

What are the two strands in a double helix held together by?

Weak Hydrogen Bonds

Prokaryotes

Circular shaped DNA- no nucleus

How do prokaryotic cells replicate?

Binary Fission

Chromosomes undergo \_____________________ replication because each strand is complementary and has info to create another strand.

semi-conservative

What does DNA helicase do?

Unzips the molecule (hydrogen bonds between base pairs are broken) to separate strands

"Twisted latter" shape of DNA

Double Helix

As cells increase in size, their SA:V does this

Decreases ( makes the cell less efficient)

The smaller the cell, the higher this is

Surface Area:Volume

Compared to small cells, large cells have more trouble doing this

Moving materials in and out of the cell

Of S.Area and Volume, which one increases faster?

Volume

Cells spend most of their time in this phase

Interphase

The three stages of interphase (in order)

G1, S, G2

The division of the cytoplasm

Cytokinesis

Dividing the nucleus to make an identical copy

Mitosis

Chromosomes are copied during this stage (be specific)

S stage of interphase

The first stage of mitosis

Prophase

The stage of mitosis when the nuclear envelope dissolves

Prophase

When the chromosomes align in the middle of the cell

Metaphase

Sister chromatids separate during this stage of mitosis

Anaphase

Cytokinesis begins during this stage of mitosis

Telophase

These are attached by a centromere

Sister Chromatids

The protein belt that attaches two sister chromatids

Centromere

The structure that appears in the middle of two new cells in plant cytokinesis

Cell Plate

A disease of the cell cycle (uncontrolled mitosis)

Cancer

Why do cells divide?

To grow, reproduce, repair and replace

Why are smaller cells more efficient?

They have a smaller volume with a bigger surface area so there is a higher area to exchange materials through the cell membrane like food, oxygen, water and waste.

What are the two new cells formed in cell division called?

Daughter Cells

Asexual Reproduction

Reproduction that involves a single parent

Example of Asexual Reproduction

Bacteria reproduce by binary fission (splitting into two new cells)- identical copy

The offspring produced are normally genetically \__________________ to the single cell that produced them.

identical

Sexual Reproduction

Reproduction that involves more than one parent

What is it called when sex cells fuse into a single cell before the offspring can grow?

Fertilization

In what part of cell division does the cytoplasm divide?

Cytokinesis

How many chromosomes are in every human somatic cell?

46

What happens in the G1 Phase of Interphase?

Growth

What happens in the S Phase of Interphase?

Synthesis of DNA (new chromosomes)

What happens in the G2 Phase of Interphase?

Organelles, proteins and molecules for cell division are synthesized

In what mitotic phase, do chromosomes coil up?

Prophase

In what mitotic phase, do spindle fibers form?

Prophase

In what mitotic phase, do the centrioles move to the poles?

Prophase

In what mitotic phase, does the nucleolus dissolve into the cytoplasm?

Prophase

In what mitotic phase, does the nuclear envelope break down?

Prophase

In what mitotic phase, do the chromosomes line up across the center of the cell along the equator?

Metaphase

In what mitotic phase, do the spindle fibers attach to the centromere of chromosomes?

Metaphase

In what mitotic phase, do the sister chromatids pull apart and become individual chromosomes?

Anaphase

In what mitotic phase do the chromosomes move to opposite ends of the spindle fibers?

Anaphase

What mitotic phase "undoes" prophase?

Telophase

In what mitotic phase, do chromosomes uncoil?

Telophase

In what mitotic phase, do two nuclear envelopes reform around chromosomes?

Telophase

In what mitotic phase, do the spindle fibers break down?

Telophase

In what mitotic phase does the nucleus become visible in each nucleus?

Telophase

What happens in the cytokinesis of animal cells?

The cell membrane pulls inward to divide the cells and forms a cleavage furrow

What happens in the cytokinesis of plant cells?

The cell plate divides the cytoplasm and forms a cell wall

What is a disease of the cell cycle?

Cancer

\_______________________ cells carry out the jobs that multicellular organisms need to stay alive.

Differentiated

\___________ cells are the unspecialized cells from which differentiated cells develop.

Stem

This enzyme begins transcription by both unwinding and aligning mRNA nucleotides

RNA polymerase

The transcript of ATG

UAC

The site of transcription in eukaryotes

Nucleus

The site of transcription in prokaryotes

Cytoplasm

The three sequential nucleotides found on the mRNA transcript

Codon