cells

Question 1

Cell

Answer 1

Fundamental unit of any organism
the cell maintains life

Question 2

3 Parts of the cell

Answer 2

Cell membrane (Plasma membrane)
Cytoplasm
Nucleus

Question 3

Cell Membrane

Answer 3

Controls movement in and out of the cell, cell-cell interactions
Selectively permeable= “Picky”
Composed of phospholipid bilayer
Hydrophilic heads/Hydrophobic tails

Question 4

Cell Membrane- Transport

Answer 4

PASSIVE- no energy required, simple diffusion, facilitated diffusion, osmosis
ACTIVE- energy required, exocytosis, endocytosis (phagocytosis, Pinocytosis)

Question 5

Simple Diffusion

Answer 5

Movement of molecules from an ares of higher concentration (down)
Factors that affect diffusion rate:
Temperature, molecular weight, steepness of concentrated gradient, surface area, permeability

Question 6

Facilitated Diffusion

Answer 6

same as simple diffusion except molecules are ferried accross the membrane by a carrier

Question 7

Osmosis

Answer 7

WATER only
movement of water through higher concentration to lower concentration
water moves to higher concentration of solutes (salt)

Question 8

Tonicity (osmosis)

Answer 8

Hypertonic- cell shrinks (more salt outside)
Isotonic- cell remains same size (salt in and out =)
Hypotonic- Cell swells and may burst (more salt inside)

Question 9

Active Transport

Answer 9

Requires ATP
substance moving from low to high concentration (up)
Types: sodium-potassium pump, endocytosis, exocytosis

Question 10

Cytoskeleton

Answer 10

“cell skeleton” maintains cell shape, anchors organelles, or assist in movement
1.Mirofiliaments: 6nm thick made of actin protein, form terminal web
2.Intermediate filament- 8-10nm thick, within skin cells, made of keratin, give cell shape, reduce stress
3.MIcrotubules- 25nm thick, protein tubulin, radiate from centrosome, maintain cell shape, hold organelles, act as railroad tracks for walking motor proteins

Question 11

Cytoplasm

Answer 11

Liquid that contains the organelles

Question 12

Endoplasmic Reticulum (ER)

Answer 12

-Rough ER: Studded with ribosomes (makes proteins)
-Smooth ER: NO ribosomes (makes lipids)

Question 13

Ribosomes

Answer 13

Make proteins!
they read coded genetic messages and assemble amino acids into proteins specified by the code

Question 14

Golgi Apparatus

Answer 14

system of cisterns that synthesizes carbohydrates and puts finishing touches on protein synthesis
Functions : refines, packages, delivers via vesicles, carb/sugar production

Question 15

Vesicles

Answer 15

membranous sacs pinched from golgi which surrounds the protein product to the cell membrane for secretion or to another organelle within the cell for use

Question 16

Mitochondira

Answer 16

“POWERHOUSE OF THE CELL”
usable energy is produced in the form of ATP

Question 17

Lysosomes

Answer 17

“garbage disposals” of cell contain digestive enzymes which dispose of cellular debris & worn cellular parts
- autophagy- digestion of cell’s surplus organelles
- autolysis- “cell suicide”: digestion of a surplus cell by itself

Question 18

Peroxisomes

Answer 18

similar to lysosomes, made by ER
-neutralize free radicals, detoxify alcohol, other drugs, and a variety of blood-borne toxins.

Question 19

centrioles

Answer 19

a short cylindrical assembly of microtubules arranged in 9 groups of 3 microtubules each
2 centrioles lie perpendicular to each other within the centrosomes
- play an important role in cell division

Question 20

Nucleus

Answer 20

houses genetic material (DNA) which directs all of the cells activites
is enclosed in the nuclear envelope with nuclear pores (tiny hole)
Nucleolus- located the center of the nucleus. site of ribosome synthesis.
new ribosomes exit through pores

Question 21

Genes

Answer 21

segment of DNA coding for the synthesis of a specific protein
genome- all the genes of one person (humans have 20,000)

Question 22

DNA

Answer 22

Deoxyribose (double helix)
Nucleotides= base, sugar, phosphate group
4 bases= Adenine(A)-Thymine(T), Guanine(G)-Cytosine(C)

Question 23

RNA

Answer 23

Ribose (single strand)
4 bases= Adenine(A)-Uracil(U), Guanine(G)-Cytosine(C)

Question 24

Transcription

Answer 24

occurs in the nucleus and is the process by which genetic information encoded in DNA is copied into a strand of RNA to direct protein synthesis

Question 25

Translation

Answer 25

occurs in the cytoplasm (at the ribosome) and is the process of reading the mRNA nucleotide sequence to determine the amino acid sequence of the newly formed protein

Question 26

Central dogma

Answer 26

DNA is self replicating
DNA is transcribed into RNA
RNA is translated into protein

Question 27

Cell cycle: Interphase

Answer 27

period from cell formation to division
G1(gap 1)- metabolically active, making proteins
S(synthesis)- DNA replicating or copying
G2(gap 2)- Active, growing

Question 28

Cell division (Mitosis)

Answer 28

prophase- spindle fibers forms, centrioles moving to opposite ends of the cell. Nuclear membrane begins to disappear.
Metaphase- chromosomes align midway along the spindle fibers
Anaphase- the chromosomes begin to separate from their daughters and appear “v-shaped”. cytokinesis begins
Telophase- identical sets of chromosomes at opposite ends of the cell. spindle fibers disappear, nuclear membranes reappear, cytokinesis completes.
Cytokinesis- division of cytoplasm

Question 29

Meiosis

Answer 29

Diploid(2n) organisms produce haploid(n) gametes
2 consecutive divisions occur after interphase, meiosis I and meiosis II
Humans are diploid organisms
- their somatic cells contain pairs of chromosomes
-their gametes are haploid, having 1 set of chromosomes

Question 30

Somatic cell

Answer 30

body cell
-has 46 chromosomes in a human
-23 pairs of chromosomes
humans have 2 different sex chromosomes, X and Y, & 22 other pairs of matching chromosomes, called autosomes