Cell Structure & Function

Question 1

Sex cells

Answer 1

Sperm cells + oocyte

Question 2

Somatic cells

Answer 2

all other cells in the human body

Question 3

Extracellular fluid (Interstitial fluid)

Answer 3

The fluid a cell is surrounded by

Question 4

Plasma membrane (cell membrane)

Answer 4

Separates cytoplasm from the extracellular fluid

Question 5

Plasma membrane - characteristics

Answer 5

-Physical isolation
-Regulates exchange with the environment
-Monitors the environment
-Structural supports
-Made of lipids, proteins, and carbohydrates

Question 6

Membrane lipids

Answer 6

-Hydrophilic heads ( toward a watery environment)
-Hydrophobic fatty-acid tails (inside membrane)

Question 7

Membrane Carbohydrates

Answer 7

• Proteoglycans, glycoproteins, and glycolipids ( extend outside cell membrane)
• Form glycocalyx

Question 8

Glycocalyx

Answer 8

-Sticky “sugar coat”
-Lubrication and protection
-Anchoring and locomotion
-Specificity in binding (receptors)
-Recognition (immune response)

Question 9

Nonmembranous organelles (direct contact w cytosol)

Answer 9

• cytoskeleton
• microvilli
• centrioles
• cilia
• ribosomes
• proteasomes

Question 10

Membranous organelles (isolated from cytosol)

Answer 10

• Endoplasmic reticulum (ER)
• Golgi apparatus
• Lysosomes
• Peroxisomes
• Mitochondria

Question 11

Cytoskeleton

Answer 11

• nonmembranous organelles
• structural proteins for shape and strength
• microfilaments, intermediate filaments, microtubules

Question 12

Microfilaments

Answer 12

• filaments composed of the protein actin
• provide additional mechanical strength, interacts w proteins for consistency
• pair w thick filaments of myosin for muscle movement

Question 13

Intermediate filaments

Answer 13

• nonmembranous organelle
• durable (collagen)
• strengthen cell and maintain shape, stabilize organelles, stabilize cell position

Question 14

Microtubules

Answer 14

-nonmembranous organelle
-large, hollow tubes of tubulin protein
-attach to the centrosome, strengthen cell and anchor organelles
-change cell shape, move vesicles within the cell
-form spindle apparatus

Question 15

Microvilli

Answer 15

-nonmembranous organelle
- increase surface area for absorption
- attach to cytoskeleton

Question 16

Centrioles

Answer 16

-nonmembranous organelle
- in the centrosome (centrosome: cytoplasm surrounding centriole)
- centrioles form spindle apparatus during cell division

Question 17

Cilia

Answer 17

• nonmembranous organelle
• cilia move fluids across the cell surface

Question 18

Ribosomes

Answer 18

• nonmembranous organelle
• build polypeptides in protein synthesis
• Two types: Free ribosomes and Fixed ribosomes

Question 19

Free ribosomes

Answer 19

• in cytoplasm
• manufacture proteins for cell

Question 20

Fixed ribosomes

Answer 20

• attached to ER
• manufacture proteins for secretion

Question 21

Proteasomes

Answer 21

• nonmembranous organelle
• Contain enzymes (proteases)
• disassemble damaged proteins for recycling

Question 22

Endoplasmic reticulum

Answer 22

• membranous organelle
• Synthesis of proteins, carbohydrates, and lipids
• Storage of synthesized molecules and materials
• Transport of materials within the ER
• Detoxification of drugs or toxins
  Two types: smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER)

Question 23

Smooth endoplasmic reticulum

Answer 23

• no ribosomes attached
• synthesize lipids and carbohydrates:
  *phospholipids and cholesterol (membranes)
  *steroid hormones (reproductive system)
  *glycerides (storage in liver and fat cells)
  *glycogen (storage in muscles)

Question 24

Rough endoplasmic reticulum

Answer 24

• surface covered with ribosomes
• active in protein and glycoprotein synthesis
• folds polypeptides protein structures
• encloses products in transport vesicles

Question 25

Golgi apparatus

Answer 25

- membranous organelle - vesicles enter forming face and exit maturing face: secretory vesicles, membrane renewal vesicles, and lysosomes

Question 26

Secretory vesicles

Answer 26

- modify and package products for exocytosis

Question 27

Membrane renewal

Answer 27

add or remove membrane components

Question 28

Lysosomes

Answer 28

carry enzymes to the cytosol

Question 29

Lysosome functions

Answer 29

- clean up inside cells *break down large molecules *attack bacteria *recycle damaged organelles *eject wastes by exocytosis - autolysis (self-destruction of damaged cells) *lysosome membranes break down *digestive enzymes released *cell decomposes *cellular materials recycle

Question 30

Peroxisomes

Answer 30

- membranous organelle - enzyme-containing vesicles - break down fatty acids, organic compounds - produce hydrogen peroxide - replicate by division

Question 31

Mitochondria

Answer 31

- membranous organelle - takes chemical energy from food (glucose) - produces energy molecule ATP

Question 32

Aerobic metabolism (cellular respiration)

Answer 32

- Mitochondria use oxygen to break down food and produce ATP * Glucose + oxygen + ADP ---> carbon dioxide + water + ATP * -

Question 33

Glycolysis

Answer 33

- Glucose to pyruvic acid (in cytosol) -no oxygen

Question 34

Tricarboxylic acid cycle (TCA cycle)

Answer 34

pyruvic acid to CO2 (in matrix)

Question 35

Electron transport chain

Answer 35

inner mitochondrial membrane

Question 36

Transcription

Answer 36

copies instructions from DNA to mRNA (in nucleus) 1. gene activation -uncoils DNA, removes histones -start (promoter) and stop codes on DNA mark location of gene: coding strand is code for protein & template strand used by RNA polymerase molecule 2. DNA to mRNA -enzyme RNA polymerase transcribes DNA: -binds to promoter (start) sequence -reads DNA code for gene -binds nucleotides to form mRNA - mRNA duplicates DNA coding stand , uracil replaces thymine 3. RNA processing -At stop signal, mRNA detaches from DNA molecule: -code is edited (RNA processing) -unnecessary codes (introns) removed -good codes (exons) spliced together -triplet of three nucleotides (codon) represents one amino acid

Question 37

Translation

Answer 37

-ribosome reads code from mRNA (in cytoplasm) - assembles amino acids into polypeptide chain -Processing * by RER and Golgi apparatus produce protein